The 2015–2016 El Niño, one of the three strongest on record, is officially dead in the water.

More than a year after the weather-disrupting El Niño’s conception, the unusually warm seawater in the eastern Pacific Ocean has dissipated, the National Oceanic and Atmospheric Administration’s Climate Prediction Center reported June 9. During its reign, this El Niño boosted rainfall California, hastened coral bleaching and helped make 2015 the hottest year on record.

The agency estimates a 75 percent chance that El Niño’s meteorological sibling, La Niña, will take over in the coming months. La Niña conditions caused by relatively cool equatorial waters in the eastern Pacific can cause droughts in South America, heavy rainfall in Southeast Asia and can intensify Atlantic hurricane seasons.

People hooked on cocaine are more likely to stick to other habits, too. They’re also less sensitive to negative feedback that tends to push nonaddicts away from harmful habitual behaviors, new research published in the June 17 Science suggests.

The findings might help explain why cocaine addicts will do nearly anything to keep using the drug, despite awareness of its negative consequences. Instead, treatments that encourage new, healthier habits in place of drug use might click better.
Similar results have been demonstrated with mice and rats, but the effect hadn’t been well-established in humans.

There’s no pharmacological treatment approved by the U.S. Food and Drug Administration that targets cocaine addiction as there is for opioid addiction. So the best treatment currently focuses on changing patients’ behavior — and it’s not easy.

“It’s such a devastating situation for families,” says Karen Ersche, a psychologist at the University of Cambridge who led the study. Drug users “know they’ll lose their job. They’ll tell you they want to change, but still they carry on using the drug. It seems incomprehensible.”

Habits can be helpful because they free up brainpower for other things. A new driver has to think through every push of the pedal and flick of the turn signal, while an experienced one can perform these actions almost effortlessly, allowing them to also carry on a conversation. But people can also snap out of that automation when necessary, slamming on the brakes when a deer darts across the road. It’s harder for someone addicted to cocaine to get off autopilot.

Ersche and her colleagues showed sets of animal pictures to 125 people (some cocaine-dependent, others who had never chronically used drugs or alcohol). In one set of tests the participants learned through trial and error that certain responses to specific pictures would earn them points or not. In another, responding correctly let them escape an unpleasant electrical shock.
When animal pictures that once scored lots of points no longer did, the participants who weren’t using drugs adjusted to the change and were less likely to choose those pictures. Cocaine-addicted participants couldn’t adjust their behavior in the same way in light of the new information. They were also less successful at avoiding electrical shocks.

“That knowledge of something bad happening to them doesn’t really sink in,” Ersche says.

These results mirror those of another recent study showing that people with a history of drug or alcohol addiction (even though they were no longer using the substances) formed habits more easily and had a harder time changing them, says Charlotte Boettiger, a psychologist at the University of North Carolina at Chapel Hill. Boettiger led that study, published in the July Journal of Cognitive Neuroscience.

Both teams found that stimulants like cocaine seemed to influence habit formation more than other types of drugs did.

Successful behavioral treatment for cocaine addiction might take advantage of addicts’ habit-keeping tendencies, Ersche suggests.

“In some senses, the treatment community already capitalizes on this,” says Boettiger, pointing to programs that help patients replace their drug-use habits with healthier ones, like taking a walk after dinner instead of shooting up. There’s growing evidence that these strategies might work, though breaking the cycle of addiction is still tough.

Scientists don’t know whether people who form and keep habits more easily are more likely to become addicted to drugs in the first place, or whether drug addiction makes the brain more susceptible to habitual behavior. Boettiger suspects both might contribute —and that understanding the behavior and its neurological basis might someday help scientists develop medications to supplement behavior-based addiction treatments.

Harnessing the weirdness of the quantum world is difficult — fragile quantum properties quickly degrade under typical conditions. But such fragility could help migrating birds find their way, scientists report in the June New Journal of Physics. Some scientists believe birds navigate with sensitive quantum-mechanical compasses, and the new study suggests that quantum fragility enhances birds’ sense of direction.

Molecules known as cryptochromes, found within avian retinas, may be behind birds’ uncanny navigational skills (SN Online: 1/7/11). When light hits cryptochromes, they undergo chemical reactions that may be influenced by the direction of Earth’s magnetic field, providing a signal of the bird’s orientation.
“At first sight, you wouldn’t expect any chemical reaction to be affected by a magnetic field as weak as the Earth’s,” says study coauthor Peter Hore, a chemist at the University of Oxford. Quantum properties can strengthen a cryptochrome’s magnetic sensitivity, but their effect sticks around only for tiny fractions of a second. Any chemical reactions that could signal the bird would have to happen fast enough to skirt this breakdown.

But Hore and colleagues’ new simulations of the inner workings of cryptochromes show that a little bit of quantum deterioration can actually enhance the strength of the magnetic field’s effect on the chemical reactions.

According to scientists’ theories, light striking a cryptochrome produces a pair of radicals — molecules with a lonely singleton electron. These unpartnered electrons feel the tug of magnetic fields, thanks to a quantum property known as spin, which makes them behave a bit like tiny bar magnets. But those minuscule magnets are not enough to serve as a compass on their own — instead, the electrons’ magnetic sensitivity is the result of a strange quantum dance.

The two radicals’ electrons can spin either in the same direction or opposite directions. But rather than choosing one of these two options, the electrons pick both at once — a condition known as a quantum superposition. Quantum mechanics can describe only the odds that the electrons would be found in each configuration if forced to choose. As time passes, these probabilities oscillate up and down in a pattern that is swayed by Earth’s magnetic field. These oscillations in turn affect the rate of further chemical reactions — the details of which are not well understood — which signal to the bird which direction it’s facing.

These chemical reactions must happen quickly. As the electrons interact with their environment, their coordinated oscillations dissipate, weakening their magnetic sensitivity. But Hore and colleagues show that this isn’t the complete picture — some loss of quantumness can help birds navigate. “Not only does it not hurt the compass signal, it can make it stronger,” says physicist Erik Gauger of Heriot-Watt University in Edinburgh, who was not involved with the research.
That’s because the direction of the magnetic field also determines how quickly electrons lose their coordination, further enhancing the difference in the chemical reaction rates based on the bird’s direction in the magnetic field. So the magnetic field does double duty: It affects chemical reaction rates by altering the oscillating states of the electrons and by determining when they break off their oscillation.

Although similar types of sensitivity-boosting effects have been suggested before, they weren’t based on a cryptochrome model, says Gauger.

It’s still not certain that birds navigate with cryptochromes at all, says Klaus Schulten, a computational biophysicist at the University of Illinois at Urbana-Champaign. More research is needed to understand the details of how the cryptochromes might function. “There, this paper is very valuable,” he says. “It’s an interesting idea that’s worth pursuing.”

When snorkelers discovered what appeared to be ancient stonework off the coast of the Greek island of Zakynthos in 2013, archaeologists sent to the site thought the odd rocks might be the ruins of an ancient city. But among the columns, bagel-shaped rings and paving stone‒like rocks, they found no telltale pottery shards or other artifacts. Soon after, geochemist Julian Andrews of England’s University of East Anglia and colleagues dove down to the supposed ruins and collected samples.

Turns out, the so-called Lost City of Zakynthos was built by microbes, not by ancient Greeks. What appear to be submerged Greek ruins are actually the fossilized remains of sediments laid down by methane-chomping microbes millions of years ago, the researchers report in the September Marine and Petroleum Geology.
The formations are the creation of microbes living in vents below the seafloor where methane-rich fluids seeped toward the surface around 3 million to 4 million years ago, the researchers’ analysis suggests. As those microbes feasted on the methane, their excretions produced carbonate minerals that formed large hollow structures. Over time, erosion exposed those structures on the seafloor. While not an archaeological treasure trove, the finding could help scientists learn more about the region’s geologic past.

The researchers even penned a helpful maxim to mark their discovery: “Columns and pavements in the sea, not always antiquities will be.”

“Junk DNA” may be an essential part of a worm’s inheritance.

Parts of this not-so-disposable DNA serves as a “watermark” to authenticate a Caenorhabditis elegans roundworm’s own genes and distinguish them from foreign genes that need to be shut down, researchers report in the July 14 Cell.

Genes bearing the watermarks — called PATCs — are protected against being shut down. These genes also tend to be active in the germ line (eggs and sperm and the cells that give rise to them). Genes without authentication codes get turned off, especially in the germ line, the researchers discovered. That raises the possibility that other species, perhaps even humans, issue their own germline gene work permits.
Researchers have known that C. elegans’ set of genetic instructions, its genome, is littered with PATCs (short for periodic An/Tn clusters), but didn’t know why. PATCs are short stretches of the DNA building blocks adenine or thymine separated by other building blocks, or bases; each run goes about 10 bases on average until the start of the next A or T cluster (for instance, TTTTTaatggAAAA etc.). About 10 percent of the worm’s genome is marked with the A or T clusters, says study coauthor Christian Frøkjær-Jensen, a geneticist at Stanford University.

While other animals don’t seem to have the regular patterns of A’s and T’s exactly like C. elegans does, “the general idea that species can mark segments of their genomes and protect them from silencing … could apply to other organisms,” says Andrew Spence, a geneticist at the University of Toronto who was not involved in the study.

In 2006, Stanford University geneticist Andrew Fire and colleagues pointed out that the A-T tattoos were often associated with genes that are active in the germ line. Those watermarks were found in filler DNA, called introns, sandwiched between the parts of a gene containing the information used to make protein. Introns are snipped out and thrown away before an RNA copy of a gene is read by protein-building machinery. Introns sometimes contain information about how to regulate genes. That seems to be what the PATCs are doing.

Fire and colleagues postulated that the PATCs helped C. elegans protect its own genes from being disabled by molecular defense mechanisms that halt the incursion of foreign DNA. (Fire won the 2006 Nobel Prize in physiology or medicine (SN: 10/7/06, p. 229) for the discovery of one such mechanism, a gene-silencing system called RNA interference or RNAi.) Alien DNA from viruses or selfish bits of genetic material known as transposons, or jumping genes, can wreak havoc on a genome, damaging genes that they hop into. It is important to stop the jumping genes in the germ line because DNA in those cells will be passed on to future generations.

To combat the jumpers, C. elegans and other organisms deploy an army of small interfering RNAs that shred RNA copies of foreign genes. Other small RNAs, known as piRNAs, direct cell machinery that stretches molecular hazard tape across DNA where transposons and other aliens settle. Such off-limits territory is called heterochromatin, and genes there are turned off. Sometimes, though, some important native genes that need to stay on get trapped behind the lines. PATCs may be the operating permits that let native genes in heterochromatin remain active.
In 2006, Fire and colleagues had no data to back up their idea. The new study puts Fire’s hypothesis to the test. “Oh my gosh, did they test it. It is really a thorough and complete analysis,” says geneticist Susan Strome of the University of California, Santa Cruz.

In the new study, Fire, Frøkjær-Jensen and colleagues engineered a gene for a fluorescent jellyfish protein with an intron containing PATC watermarks. When the researchers inserted the PATC-containing gene in a heterochromatin region of the genome, the gene turned on and made the worm’s germline cells glow. But the same jellyfish gene without PATCs was turned off. Those results are evidence that PATCs protect genes against getting turned off. Exactly how that happens isn’t yet known.

Strome isn’t sure that other organisms need DNA certificates to allow their genes to turn on in rough neighborhoods. C. elegans worms have unusual chromosomes. Nearly two-thirds of each chromosome is heterochromatin wasteland. The PATC permits may be necessary only in such extreme cases, she says.

Fire says he’s not yet ready to declare that all junk DNA may be useful. “Certainly there is gold in what we see here,” he says, “but the question is whether it is all gold.”

Over the last three years, growing evidence has shown that electronic cigarettes are not the harmless alternative to smoking that many proponents have argued. Now, a new study traces a large share of e-cigs’ toxic gases to a heat-triggered breakdown of the liquids used to create the vapors. And the hotter an e-cig gets — and the more it’s used — the more toxic compounds it emits, the study shows.

“There is this image that e-cigarettes are a lot better than regular cigarettes, if not harmless,” says Hugo Destaillats, a chemist at Lawrence Berkeley National Laboratory in California. But after his team’s new analyses, published July 27 in Environmental Science & Technology, “we are now definitely convinced that they are far from harmless.”
Electronic cigarettes draw liquids over one or more hot metal coils to transform them into vapors. Those liquids — propylene glycol, glycerin or a mix of the two — are food-grade solvents laced with flavorings and usually nicotine.

The Berkeley team used two current models of e-cigs and three different commercially available e-liquids. The experimental setup mechanically drew air through the devices to create the vapors that a user would normally inhale.
Toxic aldehydes (such as formaldehyde, acetaldehyde and acrolein) were at negligible levels in the starting e-liquids, Destaillats notes. But the chemistry of the vapors varied as the e-cig device heated up: The first puffs contained somewhat less of the aldehydes than later puffs.
The new data show that “through the process of vaping, you are generating almost 1,000-fold higher emissions of those same compounds. And that is from the thermal degradation of the solvents,” Destaillats says.

Some devices can vary the voltage used to heat their coils. Higher voltages produced hotter conditions and more of the toxic aldehydes, which are probable or suspected carcinogens. Acrolein is also a potent irritant of the eyes and airways.

With a rise from 4.3 to 4.8 volts, the jump in emissions “goes exponential,” Destaillats adds, particularly “for the three aldehydes that are among the most harmful compounds present in the vapor.” Users could inhale up to 165 micrograms of these aldehydes per puff, the study found.

In their first tests, the chemists used a new e-cigarette for each puffing session. But in a second set of tests, they used one device over and over at its high-voltage setting. After the ninth 50-puff cycle, the toxic aldehyde emission rate had climbed by another 60 percent. This was consistent with a buildup on or near the heating element of what has come to be known colloquially as “coil gunk,” the researchers say. “Heating these residues would provide a secondary source of the volatile aldehydes.”

The data on changes in the vapor composition of “aged” e-cigarettes “is something new,” notes toxicologist Maciej Goniewicz of the Roswell Park Cancer Institute in Buffalo, N.Y. And using a better analytical technique than others have employed, he says, the Berkeley team turned up new toxicants — such as propylene oxide and glycidol — which neither his group nor others had detected in e-cig vapors.

CHICAGO — Particle physicists’ hopes have been dashed. A possible new particle hasn’t been sighted in new data from the Large Hadron Collider, scientists reported August 5 at the International Conference on High Energy Physics.

Physicists from LHC experiments CMS and ATLAS first unveiled hints of the new particle in December 2015 (SN: 1/9/16, p. 7). In the months that followed, enthusiastic physicists published hundreds of papers proposing theoretical explanations (SN: 5/28/16, p. 11).

Evidence of the particle, in the form of a bump on a plot — an excess of events at a particular energy — popped up after the LHC, at the European particle physics laboratory CERN near Geneva, began smashing together protons at a newly boosted energy of 13 trillion electron volts. The hint appeared in collisions that produced two high-energy photons.
LHC physicists had previously cautioned that the bump could be due to a random fluctuation that would disappear with more data. That caution appears to have been warranted: Neither experiment now shows any evidence of a wayward bump.

The bump “unfortunately is not confirmed by the new data,” CMS physicist Chiara Ilaria Rovelli of the National Institute for Nuclear Physics in Rome said in a session at ICHEP. Similarly, in ATLAS data, “there is no significant excess seen,” said CERN physicist Bruno Lenzi of the ATLAS collaboration.

Because the evidence had emerged independently in the two experiments, scientists had been especially hopeful that more data would increase the strength of the signal. Now, said Rovelli, “I would say that was a coincidence.”

Before the demise of Japan’s latest X-ray satellite, Hitomi, the probe might have put to rest speculation about radiation from dark matter in a cache of galaxies.

In 2014 astronomers reported that several galaxy clusters appeared to inexplicably produce X-ray photons with energies of about 3.5 kiloelectron volts. The researchers suggested that the radiation could be coming from the decay of sterile neutrinos — hypothetical particles that are one candidate for the elusive dark matter that is thought to bind galaxies and clusters together.

Before the Hitomi X-ray satellite (aka ASTRO-H) failed on March 26, it got a look at the Perseus galaxy cluster, a horde of galaxies about 232 million light-years away. The telescope saw no sign of the previously reported X-ray photons, scientists report in a paper online July 25 at arXiv.org. A similar search of the dwarf galaxy Draco last year with the XMM-Newton satellite also failed to turn up the mystery X-rays. The no-show photons make it less likely that sterile neutrinos are the dark matter particles that scientists have been looking for.

Hitomi spun itself to death less than six weeks after it launched, when a problem with its control system caused the spacecraft to rotate out of control. The Japanese space agency is considering building Hitomi 2.0 for a possible launch in 2020.

Rooting out terrorism
Anthropologists have moved to the front lines to determine what drives people to join terrorist organizations such as the Islamic State. New research shows that the most committed ISIS fighters revere Islamic law and identify closely with a small group of comrades, Bruce Bower reported in “Deadly devotion” (SN: 7/9/16, p. 18).

Some readers noted similarities between researcher Scott Atran’s work and philosopher Eric Hoffer’s 1951 book The True Believer. The book discusses the psychological causes of fanaticism that can be seen in political and religious movements throughout history. “It’s nice to have a scientific patina applied to Hoffer’s work, but his contributions to explaining the p-sychological bases for mass movements should always be credited,” wrote Michael Rethman.
Atran agrees with some of Hoffer’s ideas about the general conditions of fanatic devotion, including unity and self-sacrifice. But he is skeptical of other proposed conditions such as self-alienation and insecurity. “In any event, our research was driven more by trying to figure out, test and validate the cognitive and social conditions of devotion unto death regardless of personality factors,” he writes. “Hoffer provides historical comparison and depth to some of these ideas. But our task is to see what can be scientifically validated as right.”

Diet dilemma
Some microbes that live in the gut might cause obesity by converting fats in food into chemical signals that tell the brain to pack on the pounds, Tina Hesman Saey reported in “Microbial signals influence obesity” (SN: 7/9/16, p. 7).

“Then why do the olive oil fats in the Mediterranean diet not cause obesity? Why do the blubber fats in traditional Inuit diets not cause obesity? Lots more research to be done,” reader Laura Hamilton wrote online.

Saey agrees that more research is needed, but the answer may be more complex than microbes alone. Some research, for example, is already hinting that a diet’s effects may depend more on who is doing the eating than on what they are eating. Rodents on the same diet, but with different genetic makeups, may not be equally prone to g-aining weight, a recent study suggests (SN: 8/20/16, p. 13). The same could be true for people. “So while Inuit diets may not promote obesity for them, someone else may pack on pounds after munching on blubber. Olive oil may not be healthy for everyone either,” Saey says. “Researchers are just at the beginning of understanding how genetics, microbes and diet work together to influence health.”
Dog days of yore
Dogs may have been domesticated at least twice, in Europe and Asia, during the Stone Age. G­enetic analysis revealed that over time, East Asian dogs replaced dogs native to Europe, Tina Hesman Saey reported in “DNA tells of dual origins for dogs” (SN: 7/9/16, p. 15).

Some online readers wondered if disease played a role in shaping the ancient dog populations. “Given the ability of wolves, dogs and humans to travel long distances, it wouldn’t be surprising if the Asian proto-dogs carried in fleas, internal parasites or other diseases and killed off a good portion of the European proto-dogs,” Onyxhawke wrote. Online reader kudjomojo agreed, suggesting that East Asian dogs’ genomes could have offered disease resistance.

Disease spread often comes with migration to new lands. “It may also have been that the Asian dogs didn’t bring the diseases but were less susceptible to diseases that may have killed European dogs,” Saey says. Other factors could have played a part, too: Asian dogs may have had physical or behavioral traits that made them more appealing to humans and helped them become the top dogs in Europe. “It’s never a gene-to-gene or genome-to-genome fight, but rather what traits the underlying genetic makeup influences that decide which dogs will have their day,” she says.

The brains of human ancestors didn’t just grow bigger over evolutionary time. They also amped up their metabolism, demanding more energy for a given volume, a new study suggests.

Those increased energy demands might reflect changes in brain structure and organization as cognitive abilities increased, says physiologist Roger Seymour of the University of Adelaide in Australia, a coauthor of the report, published online August 31 in Royal Society Open Science.

Blood vessels passing through bones leave behind holes in skulls; bigger holes correspond to bigger blood vessels. And since larger vessels carry more blood, scientists can use hole size to estimate blood flow in extinct hominids’ brains. Blood flow in turn indicates how much energy the brain consumed. (In modern humans, the brain eats up 20 to 25 percent of the energy the body generates when at rest.)
Seymour and colleagues focused on the carotid arteries, the vessels that deliver the bulk of the brain’s blood. The team looked at nearly three dozen skulls from 12 hominid species from the last 3 million years, including Australopithecus africanus, Homo neanderthalensis and Homo erectus. In each, the researchers compared the brain’s overall volume with the diameter of the carotid artery’s tiny entrance hole at the base of the skull.
“We expected to find that the rate of blood flow was proportional to the brain size,” Seymour says. “But we found that wasn’t the case.” Instead, bigger brains required more blood flow per unit volume than smaller brains.
The boost in blood flow, and therefore metabolism, suggests two possible conclusions, Seymour says. As hominid brains got bigger, they might have packed in more nerve cells, or their nerve cells might have fired more frequently. Either way, he argues, the increased blood flow suggests greater brainpower, perhaps reflecting reorganization of the brain over the course of evolution.

But not all of the blood coming into the brain through the carotid arteries directly supports mental prowess. “You need more complicated wiring for bigger and more cognitively advanced brains,” says Dean Falk, an evolutionary anthropologist at Florida State University in Tallahassee. “But those brains have more advanced cooling requirements.”

Some of the blood coming in through the carotid arteries absorbs heat generated by the brain’s activity and then drains away, helping to keep the brain cool, Falk says. So while the study is a scientifically rigorous look at metabolism and blood flow toward the brain, she says, a follow-up study is needed to account for the blood moving away from the brain.