Three high-energy neutrinos have been spotted traveling in tandem.
The IceCube Neutrino Observatory in Antarctica detected the trio of lilliputian particles on February 17, 2016. This is the first time the experiment has seen a triplet of neutrinos that all seemed to come from the same place in the sky and within 100 seconds of one another. Researchers report the find February 20 on arXiv.org.
Physicists still don’t know where high-energy neutrinos are born. The three neutrinos’ proximity in time and space suggests the particles came from the same source, such as a flaring galaxy or an exploding star. But the scientists couldn’t rule out the possibility of a fluke — the triplet could simply have been the result of accidental alignment between unassociated neutrinos.
Eight different telescopes followed up on the neutrino triplet, checking for some sign of the particles’ origins. The telescopes, which searched for gamma rays, X-rays and other wavelengths of light, found nothing clearly associated with the particles. But scientists were able to rule out some possible explanations, like a nearby stellar explosion caused by the collapse of a dying star.
Here’s one good reason why people often take medications and use health products that don’t live up to expectations or just don’t work — digital word of mouth.
The reviews can be glowing. Take this scuttlebutt about a cholesterol treatment: “I have been using this product for 2 years. Within the first 3 – 4 months my cholesterol was down 30 points. Just got cholesterol tested last week: down from 245 to 196.”
That’s incredible. It might even be true. But the big picture is alarming: Patients’ online reviews of three over-the-counter drugs — two for lowering cholesterol and one for losing weight — greatly exaggerate how well these substances actually work for most people, says psychologist Mícheál de Barra of the University of Aberdeen in Scotland. Online reviewers portray these medications as working three to six times better than they do in clinical trials that randomly assign drugs or placebos to broad samples of volunteers, he says.
“To learn what works in medicine, you need systematically collected data, usually randomized clinical trials,” de Barra says. “It’s very risky to rely on observations and word of mouth, whether it’s electronic or in person.”
Online reviewers probably aren’t lying, at least not in most cases. Neither are online review readers unrealistically optimistic about health treatments. The problem is that people who benefit most from a medication are especially apt to post their experiences online. Review readers get bamboozled by a wave of positive recommendations that don’t accurately represent how a drug works, or doesn’t work, for people in general.
The duping doesn’t end there. Direct word of mouth about medical treatments, as well as glowing testimonials about health products in advertisements, also traffic in positively skewed information.
In some cases, science does, too. Researchers have recently raised alarms about the “file-drawer problem,” in which studies that find no statistical effects are not published (SN: 5/19/12, p. 26). Published studies reporting positive effects then look unjustifiably bulletproof.
Clinical trials can tilt results in other ways as well. Authors of published trials often fail to preregister details of what they plan to study and how they’ll measure it, enabling data manipulation, selective reporting of results and self-serving interpretations of findings. Clinical trials report patients’ “average” responses to, say, an anticholesterol drug, but do a poor job of predicting which individuals will benefit from that treatment. “Published evidence from randomized trials is already an amalgam of evidence-based medicine and hearsay,” notes Stanford University epidemiologist John Ioannidis. Online reviews are just old-fashioned word of mouth with a global bullhorn. But they offer one way to quantify the positive bias inherent in so much communication about medical treatments. Patients’ medication reviews that include numerical information, such as cholesterol levels before and after taking an anticholesterol drug, represent what Ioannidis calls “evidence-based hearsay.” Even if patients’ reviews rate treatments with a star system rather than including quantified measures of some kind, those opinions become powerful hearsay evidence for other patients, Ioannidis suspects.
De Barra evaluated 908 online reviews of two cholesterol reduction products, Benecol caramel smart chews and CholestOff, written on or before March 18, 2015. He also assessed 767 reviews of a weight-loss drug, Alli (orlistat), written on or before February 28, 2015.
Benecol reviewers reported a not-too-shabby average cholesterol decline of 45 milligrams per deciliter, versus a small average decline of 14 milligrams per deciliter in nine clinical trials. Respective numbers for CholestOff were 31 milligrams per deciliter and 13 milligrams per deciliter. Alli reviewers reported an average weight loss of about 10 kilograms after taking the drug for three months, versus an average of about two or three kilograms in two clinical trials. That disparity widened slightly after taking Alli for seven months.
Each drug garnered mainly positive reviews, some reporting effects far larger than the average, peppered with a few pans, De Barra reports in the March Social Science & Medicine.
What’s particularly concerning is that these three medications displayed small or negligible effects in clinical trials that probably already inflated how well the drugs work, Ioannidis says. So people searching for help in lowering cholesterol or shedding pounds may instead be getting a massive dose of disappointment from online reviews.
Online reviews can also exaggerate a treatment’s worst effects, whether real or alleged. Evidence-based hearsay may be particularly catchy online and in person when it’s frightening, de Barra suspects.
The anti-vaccination movement provides a potent example, due in part to the success of vaccines. When people face no immediate threat from measles or other infectious diseases, anti-vaccine stories may go viral, so to speak, thanks to misapplied but deeply felt intuitions. Two cognitive scientists, Helena Miton of Central European University in Budapest and Hugo Mercier of the Cognitive Sciences Institute in Bron, France, proposed this scenario in the November 2015 Trends in Cognitive Sciences.
However medical treatments acquire halos or horns, only well-conducted, transparent clinical trials can identify effective medical treatments, such as childhood vaccinations, and their potential side effects, Ioannidis says. But an ominous research trend is gathering steam, he warns. Researchers, professional societies, funders and lobbyists increasingly push to replace clinical trials of randomly selected volunteers with studies of interventions for select samples of people who eat certain foods, take certain drugs or behave in certain ways. The latter investigations may inflate a treatment’s effects even more than online patient reviews do, Ioannidis asserts.
Perhaps a new wave of studies showing how evidence-based hearsay misrepresents many medications will be just what the doctor ordered to resuscitate evidence-based medicine, he muses.
Remnants of a royal palace in southern Mexico, dating to between around 2,300 and 2,100 years ago, come from what must have been one of the Americas’ earliest large, centralized governments, researchers say.
Excavations completed in 2014 at El Palenque uncovered a palace with separate areas where a ruler conducted affairs of state and lived with his family, say archaeologists Elsa Redmond and Charles Spencer, both of the American Museum of Natural History in New York City. Only a ruler of a bureaucratic state could have directed construction of this all-purpose seat of power, the investigators conclude the week of March 27 in Proceedings of the National Academy of Sciences.
The royal palace, the oldest such structure in the Valley of Oaxaca, covered as many as 2,790 square meters, roughly half the floor area of the White House. A central staircase connected to an inner courtyard that probably served as a place for the ruler and his advisors to reach decisions, hold feasts and — based on human skull fragments found there — perform ritual sacrifices, the scientists suggest. A system of paved surfaces, drains and other features for collecting rainwater runs throughout the palace, a sign that the entire royal structure was built according to a design, the researchers say.
El Palenque’s palace contains no tombs. Its ancient ruler was probably buried off-site, at a ritually significant location, Redmond and Spencer say.
Animal-hair cords dating to the late 1700s contain a writing system that might generate insights into how the Inca communicated, a new study suggests.
Researchers have long wondered whether some twisted and knotted cords from the Inca Empire, which ran from 1400 to 1532, represent a kind of writing about events and people. Many scholars suspect that these textile artifacts, known as khipus, mainly recorded decimal numbers in an accounting system. Yet Spanish colonial documents say that some Inca khipus contained messages that runners carried to various destinations. Now a new twist in this knotty mystery comes from two late 18th century khipus stored in a wooden box at San Juan de Collata, a Peruvian village located high in the Andes Mountains. A total of 95 cord combinations of different colors, animal fibers and ply directions, identified among hundreds of hanging cords on these khipus, signify specific syllables, reports Sabine Hyland. Hyland, a social anthropologist at the University of St. Andrews in Scotland, describes the khipus online April 19 in Current Anthropology.
Her findings support a story told by Collata villagers that the khipus are sacred writings of two local chiefs concerning a late 18th century rebellion against Spanish authorities.
The Collata khipus display intriguing similarities to Inca khipus, including hanging cords with nearly the same proportions of two basic ply directions, Hyland says. A better understanding of Central Andean khipus from the 1700s through the 1900s will permit a reevaluation of the earlier Inca twisted cords, she suggests.
Each Collata khipu, like surviving Inca examples, consists of a horizontal cord from which a series of cords hang. One Collata specimen contains 288 hanging cords separated into nine groups by cloth ribbons tied at intervals along the top cord. The other khipu features 199 hanging cords divided by ribbons into four groups. Knots appear only at cord ends to prevent unraveling. In contrast, proposed accounting khipus contain many knots denoting numbers.
Collata khipus’ initial hanging cords are made of bundles of colored animal hairs that represent the message’s subject matter, Hyland proposes. One khipu starts with a tuft of bright red deer hair, followed by a woven, cone-shaped bundle with metallic-colored thread. The second khipu commences with a woven, tube-shaped bundle of multicolored alpaca hair atop the remains of a red tassel. “The Collata khipus are completely unlike accounting khipus that I have been studying for over a decade,” Hyland says. Central Andean khipus generally viewed as accounting devices were often made of cotton, and they contain two main colors, between 15 and 39 cord combinations and repetitive knot sequences.
Hyland makes an “excellent case” that these cords represent syllables and probably words as well, says anthropological archaeologist Penelope Dransart of the University of Wales Trinity Saint David in Lampeter.
So far, Hyland has translated the final three cords on one khipu as the word Alluka, the name of a family lineage in Collata. She first talked to villagers and identified the lineage chief that they claimed wrote one of the khipus. Hyland then assigned the three syllables in Alluka to the trio of ending cords, assuming that the sender’s name would appear either there or at the beginning of the message. That enabled her to decipher the final cords on the second khipu as Yakapar, the name of a family lineage in a neighboring village. Heads of these lineages wrote the corded messages, Hyland suspects.
She has not yet deciphered other cords on the two khipus.
Hyland’s insights into 18th century khipus are “profoundly significant,” but won’t help to decipher Inca twisted and knotted cords, predicts Harvard University archaeologist Gary Urton. Collata villagers probably invented a phonetic form of khipu communication after the Inca civilization’s demise, when they were exposed to Spaniards’ alphabetic writing, Urton says. Inca khipus show no signs of cord combinations that corresponded to particular speech sounds, he asserts.
Thanks to the new discoveries, though, “we have hope that at least some khipus might be understood,” says archaeologist Jeffrey Splitstoser of George Washington University in Washington, D.C. Before Hyland’s report, Splitstoser thought it likely that colored threads on khipus had arbitrary meanings assigned by their makers, making them indecipherable. He studies khipus from the Wari empire, which flourished in the Peruvian Andes from around 600 to 1000 (SN: 5/10/03, p. 302).
Officials at several museums with khipu collections have classified as forgeries a few animal-hair specimens that resemble the Collata khipus, Hyland says. Those alleged fakes deserve a closer look for signs of writing, she contends.
A newly discovered glass frog from Ecuador’s Amazon lowlands is giving researchers a window into its heart.
Hyalinobatrachium yaku has a belly so transparent that the heart, kidneys and urine bladder are clearly visible, an international team of researchers reports May 12 in ZooKeys. Researchers identified H. yaku as a new species using field observations, recordings of its distinct call and DNA analyses of museum and university specimens.
Yaku means “water” in Kichwa, a language spoken in Ecuador and parts of Peru where H. yaku may also live. Glass frogs, like most amphibians, depend on streams. Egg clutches dangle on the underside of leaves, then hatch, and the tadpoles drop into the water below. But the frogs are threatened by pollution and habitat destruction, the researchers write. Oil extraction, which occurs in about 70 percent of Ecuador’s Amazon rainforest, and expanding mining activities are both concerns.
When faced with rushing floodwaters, fire ants are known to build two types of structures. A quickly formed raft lets the insects float to safety. And once they find a branch or tree to hold on to, the ants might form a tower up to 30 ants high, with eggs, brood and queen tucked safely inside. Neither structure requires a set of plans or a foreman ant leading the construction, though. Instead, both structures form by three simple rules:
If you have an ant or ants on top of you, don’t move. If you’re standing on top of ants, keep moving a short distance in any direction. If you find a space next to ants that aren’t moving, occupy that space and link up. “When in water, these rules dictate [fire ants] to build rafts, and the same rules dictate them to build towers when they are around a stem [or] branch,” notes Sulisay Phonekeo of the Georgia Institute of Technology in Atlanta. He led the new study, published July 12 in Royal Society Open Science.
To study the fire ants’ construction capabilities, Phonekeo and his Georgia Tech colleagues collected ants from roadsides near Atlanta. While covered in protective gear, the researchers dug up ant mounds and placed them in buckets lined with talc powder so the insects couldn’t climb out. Being quick was a necessity because “once you start digging, they’ll … go on attack mode,” Phonekeo says. The researchers then slowly flooded the bucket until the ants floated out of the dirt and formed a raft that could be easily scooped out.
In the lab, the researchers placed ants in a dish with a central support, then filmed the insects as they formed a tower. The support had to be covered with Teflon, which the ants could grab onto but not climb without help. Over about 25 minutes, the ants would form a tower stretching up to 30 mm high. (The ants themselves are only 2 to 6 mm long.) The towers looked like the Eiffel Tower or the end of a trombone, with a wide base and narrow top. And the towers weren’t static, like rafts of ants are. Instead, videos of the ant towers showed that the towers were constantly sinking and being rebuilt.
Peering into the transparent Petri dish from below revealed that the ants build tunnels in the base of a tower, which they use to exit the base before climbing back up the outside.
“The ants clear a path through the ants underneath much like clearing soil,” Phonekeo says. Ants may be using the tunnels to remove debris from inside the towers. And the constant sinking and rebuilding may give the ants a chance to rest without the weight of any compatriots on their backs, he says.
To find out what was happening inside the tower, the researchers fed half their ants a liquid laced with radioactive iodide and then filmed the insects using a camera that captured X-rays. In the film, radioactive ants appeared as dark dots, and the researchers could see that some of those dots didn’t move, but others did.
The team then turned to the three rules that fire ants follow when building a raft and realized that they also applied to towers. But there was also a fourth rule: A tower’s stability depends on the ants that have attached themselves to the rod. The top row of ants on the rod aren’t stable unless they form a complete ring. So to get a taller tower, there needs to be a full ring of ants gripping to the rod and each other.
That such simple rules could form two completely different structures is inspiring to Phonekeo. “It makes me wonder about the possibilities of living structures that these ants can build if we can design the right environment for them.”
When you think about it, it shouldn’t be surprising that there’s more than one way to explain quantum mechanics. Quantum math is notorious for incorporating multiple possibilities for the outcomes of measurements. So you shouldn’t expect physicists to stick to only one explanation for what that math means. And in fact, sometimes it seems like researchers have proposed more “interpretations” of this math than Katy Perry has followers on Twitter.
So it would seem that the world needs more quantum interpretations like it needs more Category 5 hurricanes. But until some single interpretation comes along that makes everybody happy (and that’s about as likely as the Cleveland Browns winning the Super Bowl), yet more interpretations will emerge. One of the latest appeared recently (September 13) online at arXiv.org, the site where physicists send their papers to ripen before actual publication. You might say papers on the arXiv are like “potential publications,” which someday might become “actual” if a journal prints them.
And that, in a nutshell, is pretty much the same as the logic underlying the new interpretation of quantum physics. In the new paper, three scientists argue that including “potential” things on the list of “real” things can avoid the counterintuitive conundrums that quantum physics poses. It is perhaps less of a full-blown interpretation than a new philosophical framework for contemplating those quantum mysteries. At its root, the new idea holds that the common conception of “reality” is too limited. By expanding the definition of reality, the quantum’s mysteries disappear. In particular, “real” should not be restricted to “actual” objects or events in spacetime. Reality ought also be assigned to certain possibilities, or “potential” realities, that have not yet become “actual.” These potential realities do not exist in spacetime, but nevertheless are “ontological” — that is, real components of existence.
“This new ontological picture requires that we expand our concept of ‘what is real’ to include an extraspatiotemporal domain of quantum possibility,” write Ruth Kastner, Stuart Kauffman and Michael Epperson.
Considering potential things to be real is not exactly a new idea, as it was a central aspect of the philosophy of Aristotle, 24 centuries ago. An acorn has the potential to become a tree; a tree has the potential to become a wooden table. Even applying this idea to quantum physics isn’t new. Werner Heisenberg, the quantum pioneer famous for his uncertainty principle, considered his quantum math to describe potential outcomes of measurements of which one would become the actual result. The quantum concept of a “probability wave,” describing the likelihood of different possible outcomes of a measurement, was a quantitative version of Aristotle’s potential, Heisenberg wrote in his well-known 1958 book Physics and Philosophy. “It introduced something standing in the middle between the idea of an event and the actual event, a strange kind of physical reality just in the middle between possibility and reality.”
In their paper, titled “Taking Heisenberg’s Potentia Seriously,” Kastner and colleagues elaborate on this idea, drawing a parallel to the philosophy of René Descartes. Descartes, in the 17th century, proposed a strict division between material and mental “substance.” Material stuff (res extensa, or extended things) existed entirely independently of mental reality (res cogitans, things that think) except in the brain’s pineal gland. There res cogitans could influence the body. Modern science has, of course, rejected res cogitans: The material world is all that reality requires. Mental activity is the outcome of material processes, such as electrical impulses and biochemical interactions.
Kastner and colleagues also reject Descartes’ res cogitans. But they think reality should not be restricted to res extensa; rather it should be complemented by “res potentia” — in particular, quantum res potentia, not just any old list of possibilities. Quantum potentia can be quantitatively defined; a quantum measurement will, with certainty, always produce one of the possibilities it describes. In the large-scale world, all sorts of possibilities can be imagined (Browns win Super Bowl, Indians win 22 straight games) which may or may not ever come to pass.
If quantum potentia are in some sense real, Kastner and colleagues say, then the mysterious weirdness of quantum mechanics becomes instantly explicable. You just have to realize that changes in actual things reset the list of potential things.
Consider for instance that you and I agree to meet for lunch next Tuesday at the Mad Hatter restaurant (Kastner and colleagues use the example of a coffee shop, but I don’t like coffee). But then on Monday, a tornado blasts the Mad Hatter to Wonderland. Meeting there is no longer on the list of res potentia; it’s no longer possible for lunch there to become an actuality. In other words, even though an actuality can’t alter a distant actuality, it can change distant potential. We could have been a thousand miles away, yet the tornado changed our possibilities for places to eat.
It’s an example of how the list of potentia can change without the spooky action at a distance that Einstein alleged about quantum entanglement. Measurements on entangled particles, such as two photons, seem baffling. You can set up an experiment so that before a measurement is made, either photon could be spinning clockwise or counterclockwise. Once one is measured, though (and found to be, say, clockwise), you know the other will have the opposite spin (counterclockwise), no matter how far away it is. But no secret signal is (or could possibly be) sent from one photon to the other after the first measurement. It’s simply the case that counterclockwise is no longer on the list of res potentia for the second photon. An “actuality” (the first measurement) changes the list of potentia that still exist in the universe. Potentia encompass the list of things that may become actual; what becomes actual then changes what’s on the list of potentia.
Similar arguments apply to other quantum mysteries. Observations of a “pure” quantum state, containing many possibilities, turns one of those possibilities into an actual one. And the new actual event constrains the list of future possibilities, without any need for physical causation. “We simply allow that actual events can instantaneously and acausally affect what is next possible … which, in turn, influences what can next become actual, and so on,” Kastner and colleagues write.
Measurement, they say, is simply a real physical process that transforms quantum potentia into elements of res extensa — actual, real stuff in the ordinary sense. Space and time, or spacetime, is something that “emerges from a quantum substratum,” as actual stuff crystalizes out “of a more fluid domain of possibles.” Spacetime, therefore, is not all there is to reality.
It’s unlikely that physicists everywhere will instantly cease debating quantum mysteries and start driving cars with “res potentia!” bumper stickers. But whether this new proposal triumphs in the quantum debates or not, it raises a key point in the scientific quest to understand reality. Reality is not necessarily what humans think it is or would like it to be. Many quantum interpretations have been motivated by a desire to return to Newtonian determinism, for instance, where cause and effect is mechanical and predictable, like a clock’s tick preceding each tock.
But the universe is not required to conform to Newtonian nostalgia. And more generally, scientists often presume that the phenomena nature offers to human senses reflect all there is to reality. “It is difficult for us to imagine or conceptualize any other categories of reality beyond the level of actual — i.e., what is immediately available to us in perceptual terms,” Kastner and colleagues note. Yet quantum physics hints at a deeper foundation underlying the reality of phenomena — in other words, that “ontology” encompasses more than just events and objects in spacetime. This proposition sounds a little bit like advocating for the existence of ghosts. But it is actually more of an acknowledgment that things may seem ghostlike only because reality has been improperly conceived in the first place. Kastner and colleagues point out that the motions of the planets in the sky baffled ancient philosophers because supposedly in the heavens, reality permitted only uniform circular motion (accomplished by attachment to huge crystalline spheres). Expanding the boundaries of reality allowed those motions to be explained naturally.
Similarly, restricting reality to events in spacetime may turn out to be like restricting the heavens to rotating spheres. Spacetime itself, many physicists are convinced, is not a primary element of reality but a structure that emerges from processes more fundamental. Because these processes appear to be quantum in nature, it makes sense to suspect that something more than just spacetime events has a role to play in explaining quantum physics.
True, it’s hard to imagine the “reality” of something that doesn’t exist “actually” as an object or event in spacetime. But Kastner and colleagues cite the warning issued by the late philosopher Ernan McMullin, who pointed out that “imaginability must not be made the test for ontology.” Science attempts to discover the real world’s structures; it’s unwarranted, McMullin said, to require that those structures be “imaginable in the categories” known from large-scale ordinary experience. Sometimes things not imaginable do, after all, turn out to be real. No fan of the team ever imagined the Indians would win 22 games in a row.
Orlando Brown Jr.'s first order of business as a member of the Bengals? Partner with Cincinnati's mayor in a humorous trailer for the team's Week 17 clash vs. Brown's old squad, the Chiefs.
Brown showed off his acting chops alongside the head of his new hometown.
Check it out here: The full NFL 2023 schedule will be announced Thursday, May 11.
Pureval famously got into a war of words with Kansas City stars Patrick Mahomes and Travis Kelce when the two sides battled in January for a berth in the Super Bowl. It seemed his words helped to light a fire under KC; Mahomes threw for three touchdowns as the Chiefs sent the Bengals home and marched toward another Super Bowl triumph.
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Back then, Brown was protecting Mahomes' blind side. He switched sides during the offseason, signing a four-year, $64 million deal with Cincinnati to keep rushers from putting Joe Burrow on his back. As such, his loyalties have changed, and in a show of goodwill, he offered Pureval some advice.
"Yeah, I think that was better than last time," Brown said after recording Pureval's vanilla reveal of the New Year's Eve game scheduled to be played in Kansas City. The mayor was far less fiery than when he declared Arrowhead Stadium "Burrowhead" ahead of the AFC championship game.
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Suffice to say, Mahomes and Kelce got the last laugh then. Not only did they vanquish their AFC rivals, they also were loud about it, hopping on the microphone to dish dirt.
"Know your role and shut your mouth, you jabroni," Kelce said, mimicking The Rock.
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Revenge is a dish best served cold. But it's always nice to see someone laugh at themselves after getting caught with their foot in their mouth. Brown's cameo should add intrigue to what is certain to be one of the most-watched games of the 2023 regular season.
The Golden State is at the vanguard in the United States in reducing auto emissions of nitrogen oxide gases, which help produce toxic smog and acid rain. But the NOx pollution problem isn’t limited to auto exhaust. California’s vast agricultural lands — particularly soils heavily treated with nitrogen fertilizers — are now responsible for as much as 51 percent of total NOx emissions across the state, researchers report January 31 in Science Advances. The catchall term “NOx gases” generally refers to two pollution-promoting gases: nitric oxide, or NO, and nitrogen dioxide, or NO2. Those gases react with incoming sunlight to produce ozone in the troposphere, the lowest layer of the atmosphere. At high levels, tropospheric ozone can cause respiratory problems from asthma to emphysema.
Between 2005 and 2008, regulations issued by the California Air Resources Board on transportation exhaust reduced NOx levels in cities such as Los Angeles, San Francisco and Sacramento by 9 percent per year. However, the U.S. Environmental Protection Agency has increasingly recognized nitrogen fertilizer use as a significant source of NOx gases to the atmosphere.
NOx gases are produced in oxygen-poor soils when microbes break apart nitrogen compounds in the fertilizer, a process called denitrification. The release of those gases from fertilized soils increases at high temperatures due to increased microbial activity, says Darrel Jenerette, an ecologist at the University of California, Riverside, who was not involved in the new study.
Jenerette and others have studied local NOx emissions from soils in California, but no statewide assessment existed. So Maya Almaraz, an ecologist at the University of California, Davis, and her colleagues designed a study to examine the question — both from above and below. Using a plane equipped with scientific instruments including a chemiluminescence analyzer to detect NOx gases in the atmosphere, the researchers measured the concentrations of the gases above the San Joaquin Valley, an area of California’s fertile Central Valley, over six days at the end of July and beginning of August. The team also simulated NOx emissions from soils across the state, using the San Joaquin Valley data to ensure that the simulations gave accurate results. Finally, the researchers compared those data with nitrogen fertilizer inputs, as estimated by crop type and U.S. Department of Agriculture fertilizer consumption data.
Story continues below maps Croplands are contributing 20 to 51 percent of the total NOx in California’s air, Almaraz’s team reports. In the simulations, those soil emissions were particularly sensitive to two factors: climate, especially temperature, and rates of nitrogen input. That findings suggests that regions with greater inputs of nitrogen fertilizer will also see greater soil emissions — and that the emission of NOx gases from the soils will also increase as temperatures rise in the region due to climate change.
Although food demands — and the need for fertilizer for crops — are likely to increase in the future, there are numerous possible ways to limit unwanted nitrogen fertilizer spillover, the researchers note. For example, farmers can use more efficient fertilization strategies such as adjusting how much fertilizer is used depending on specific growing stages, or planting what are called cover crops along with the target crops that enrich soils and consume the excess nitrogen.
Almaraz’s team has produced an important finding, Jenerette says. “The combination of bottom-up soil emission measurements and top-down airborne measurements provide strong evidence for their emission assessments,” he says. The finding that NOx emission rates will increase with warming temperatures also highlights the urgency of taking steps to better manage nitrogen fertilizer use in a warming world, he says.
Female polar bears prowling springtime sea ice have extreme weight swings, some losing more than 10 percent of their body mass in just over a week. And the beginnings of bear video blogging help explain why.
An ambitious study of polar bears (Ursus maritimus) in Alaska has found that their overall metabolic rate is 1.6 times greater than thought, says wildlife biologist Anthony Pagano of the U.S. Geological Survey in Anchorage. With bodies that burn energy fast, polar bears need to eat a blubbery adult ringed seal (or 19 newborn seals) every 10 to 12 days just to maintain weight, Pagano and his colleagues report in the Feb. 2 Science. Camera-collar vlogs, a bear’s-eye view of the carnivores’ diet and lifestyle secrets, show just how well individual bears are doing. The study puts the firmest numbers yet on basic needs of polar bears, whose lives are tied to the annual spread and shrinkage of Arctic sea ice, Pagano says. As the climate has warmed, the annual ice minimum has grown skimpier by some 14 percent per decade (SN Online: 9/19/16), raising worries about polar bear populations. These bears hunt the fat-rich seals that feed and breed around ice, and as seal habitat shrinks, so do the bears’ prospects. Pagano and colleagues used helicopters to search for polar bears on ice about off the Alaska coast in the Beaufort Sea. It’s “a lot of grueling hours looking out the window watching tracks and looking at whiteness,” he says. After tracking down female bears without cubs, the researchers fitted the animals with a camera collar. A full day’s doings of bears on the sea ice have been mostly a matter of speculation, Pagano says. Collar videos showed that 90 percent of seal hunts are ambushes, often by a bear lurking near a hole in the ice until a seal bursts up for a gulp of air. Videos also caught early glimpses of the breeding season and what passes for courtship among polar bears. Males, Pagano says, “pretty much harass the female until she’ll submit.”
The researchers also injected each bear with a dose of water with extra neutrons in both the hydrogen and oxygen atoms. Eight to 11 days later, the team caught the same bear to check what was left of the altered atoms. Lower traces of the special form of oxygen indicated that the bear’s body chemistry had been very active, and that the bear had exhaled lots of carbon dioxide. (The unusual form of hydrogen let scientists correct results for oxygen atoms lost in H2O, for instance when the bear urinated.)
Using CO₂ data from nine females, Pagano and his colleagues calculated the field metabolic rates for polar bears going about their springtime lives. The team found that female bears need to eat a bit more than 12,000 kilocalories (or what human dieters call calories) a day just to stay even. That estimate adds some 4,600 kilocalories a day to the old estimate. But merely maintaining weight isn’t enough for a polar lifestyle. To survive lean times, polar bears typically pack on extra weight in spring.
To get a broader view of the bears’ energy needs, similar metabolic measurements for other seasons would be useful, says physiological ecologist John Whiteman of the University of New Mexico in Albuquerque. That could help resolve whether and how much bear metabolism drops when there’s little food, a response that might protect bears during hard times. Using temperature loggers to estimate metabolic rates, he has seen only a gradual decline in metabolic rates in summer as food gets tougher to find. Winter metabolic rates remain a mystery.
Hunting success and bear activity are only part of the picture of polar bear health, says ecotoxicologist Sabrina Tartu, of the Norwegian Polar Institute, which is based in Tromsø. Tartu coauthored a 2017 paper showing that toxic pollutants such as polychlorinated biphenyls, or PCBs, can build up in bear fat. Such “pollutants could, by direct or indirect pathways, disrupt metabolic rates,” she says. So changing the climate is far from the only way humankind could affect polar bear energy and hunting dynamics.
