"zombie" outbreak in a New York City

An uncommon drug caused a "zombie" outbreak in a New York City neighborhood this past summer, and now a new report identifies the exact compound that the affected people took.The report also shows scientists how they could identify other such drugs in the future.

The mass intoxication was caused by a type of synthetic marijuana, The New York Times reported at the time. The new report specifically identifies the chemical in the drug product as "AMB-FUBINACA," and also highlights some of the unique difficulties that arise in the study of synthetic drugs. [3 Dangerous New Drug Habits in Teens]

It's not entirely clear why the drug, which was sold under the name "AK-47 24 Karat Gold," causes "zombie-like" symptoms, such as a slow response time to questions, and blank stares, said study senior author Roy Gerona, a clinical chemist at the University of California, San Francisco.

Indeed, these "zombie" symptoms are "a little uncommon" for people who take synthetic marijuana, Gerona told Live Science. Typically, the synthetic marijuana compounds found in these "mass intoxications" have more severe effects on people's health, including seizures and kidney damage, he said. But in this case, the only effect observed was the depressant, or "zombie-like," effect, he said.

But that effect appeared to be a potent one, Gerona added.

It's difficult for scientists to determine why particular drug compounds are more potent than others in humans, Gerona said. In the new study, published Dec. 14 in The New England Journal of Medicine, Gerona and his colleagues used lab tests to show that the AMB-FUBINACA compound is more potent than compounds found in other versions of synthetic marijuana. Indeed, lab tests showed that AMB-FUBINACA is actually 85 times as potent as THC (tetrahydrocannabinol), the active compound in marijuana, the researchers wrote in their report. However, these lab tests don't always translate to potency in humans, Gerona said.

"It seems like the effects we're seeing in patients only suggest that [the drug] is potent," Gerona said. But the researchers don't know whether that's because the compound is intrinsically potent or because there was a "misdosing" in the packets of the product that were sold commercially and taken by the people in New York, he said.

Synthetic marijuana is made by spraying assorted chemicals onto plant material. But "misdosing" can result — for example, if someone adds too much of the chemical to the herbal material, Gerona said.

"We couldn't know [about the potency] until we tested the effects in animal models," Gerona said.

But testing in animal models can take a long time, and by then, the particular type of synthetic marijuana may be off the market.

Indeed, the dynamic market for synthetic marijuana compounds — there are thousands of these drugs on the market, and new compounds are being synthesized constantly — makes it challenging to even create tests to look for these drugs, Gerona said.

Normally, drug tests are "targeted," Gerona said, meaning that the tests look for a specific, known compound. In other words, if someone is given a drug test for opiates and they have marijuana in their system, the test won't pick up the marijuana, he said.

But it's much trickier to test for synthetic marijuana because there are so many forms of the drug.

"There are literally thousands of designer drugs, so it's not humanly possible to actually develop a targeted" drug test for all of them, Gerona said. [9 Weird Ways You Can Test Positive for Drugs]

Testing for zombie chemicals

To find out what chemical caused people to become zombie-like in New York, Gerona and his colleagues used blood and urine samples from eight of the intoxicated people. The researchers applied a technique that collected information on all of the compounds present in each sample.

Usually, if the researchers find that one of the compounds in the samples matches the formula for any type of synthetic marijuana, "that's a tentative identification," Gerona said.

But the problem is that in order to confirm the identification, researchers must match the compound they find in the biological sample to a "commercial reference standard," he said. In some cases, this reference standard could come from a product that's on the market. But if researchers can't find the product on the market, they have to synthesize it themselves, which can take months and is very expensive, he said.

To get around this problem, Gerona and his colleagues have synthesized a number of compounds that they call "prophetic synthetic cannabinoids," or new versions of synthetic marijuana that they think will eventually show up on the market.

In this particular case, the researchers found that a metabolite of AMB-FUBINACA, or a compound formed when the body breaks down the drug, was a match with one of their "prophetic" compounds, Gerona said.

Originally published on Live Science.

Species May Have Been Polygynous

The lifetime of a glacier — an enormous slow-moving river of ice — can span many thousands of years. And while glaciers are dynamic, changes to their length and volume happen at an extremely sluggish pace.

However, over the last century a number of glaciers in mountain regions around the world dwindled significantly, diminishing in size and abandoning their farthest recorded boundaries (where they attach to land).

And a new study found with 99 percent certainty that climate change is driving their retreat, or shrinkage, with the likelihood of any other factor causing such dramatic change estimated at 1 in 100,000, the researchers found. This is the first analysis to connect individual glacier retreat to the effects of recent, global climate change. [Photos of Melt: Glaciers Before and After]

The scientists investigated 37 glaciers representing five geographic regions: Europe, Scandinavia, Asia, North America and the Southern Hemisphere. They delved into 130 years of records that documented glacier length and mass; how far the glaciers had advanced, or grew, in the past; and how much they retreated. The researchers also noted patterns in local precipitation and temperature that might have affected a glacier's size and movements.

"The big thing that we focused on was the natural fluctuations of glaciers that would have happened even without climate change," study co-author Gerard Roe, a professor of Earth and Space Sciences at the University of Washington in Seattle, told Live Science.

Roe and his colleagues applied their data to a statistical ratio known as "signal-to-noise," defining the "signal" as fluctuations driven by climate change, and "noise" as the more abundant weather-sensitive fluctuations that a glacier would normally undergo from year to year. This allowed the researchers to predict if each glacier's current state of reduced ice would have happened even without climate change.

They found that glaciers lost far more ice than could be explained by normal conditions. In some cases, glaciers retreated 10 to 15 times the distance that they would have, were climate change not a factor.

"This is an extraordinarily large departure from what these glaciers would be doing in a constant climate," Roe told Live Science.

For example, Austria's Hintereisferner glacier retreated a distance of 1.75 miles (2.8 kilometers) since 1880. According to the study, the probability that natural variations are responsible is less than 0.001 percent — 1 in 100,000.

"I was actually shocked at how far out of equilibrium these glaciers are," he said.

The study's findings represent the largest signal-to-noise ratio ever documented for global warming — "the purest signal of climate change," according to Roe. Alongside the data, the visual impact of vanishing glaciers — visible in photo comparisons that span decades — offers sobering testimony to the impact rapidly rising temperatures can have on Earth.

"These landscapes are changing before our eyes," Roe said. "I hope this is a big upgrade to our understanding of the relationship between glacier retreats and climate change."

The findings were published online Monday (Dec. 12) in the journal Nature Geoscience.

Original article on Live Science.

The ancient relative of humanity dubbed "Lucy" may have been one of a harem of gals who mated with a single male, according to research that suggests her species was polygynous.

Among the earliest known relatives of humanity whose skeletons were made for walking upright was Australopithecus afarensis, the species that included the famed 3.2-million-year-old Lucy. Members of the Australopithecus lineage, known as australopithecines, are among the leading candidates for direct ancestors of the human lineage, living about 2.9 million to 3.8 million years ago in East Africa. [Photos: New Human Ancestor Species Discovered]

To learn more about Lucy's species, researchers investigated the area of Laetoli in northern Tanzania, which previously yielded the earliest known footprints belonging to hominins— humans and related species dating back to the split from the chimpanzee lineage. Those footprints, which date to 3.66 million years ago, were excavated in 1978 at a place dubbed "site G." They are thought to belong to three members of A. afarensis walking in the same direction across wet volcanic ash.

Now, a team of researchers from institutions in Italy and Tanzania has discovered new 3.66-million-year-old tracks at Laetoli that they suggest also belonged to A. afarensis.

"It is amazing that, almost four decades after the original discovery, we have new footprints from the very same sediments," said William Jungers, a paleoanthropologist at Stony Brook University in New York who did not take part in this research. "They could have been made on the same day millions of years ago."

These footprints — a kind of ichnofossil, or trace fossil — reveal that this extinct species may have had major differences in sizes between the sexes. This difference, in turn, suggests that the species might have been polygynous, where males have multiple female mates, the researchers said. Previous research suggested the fact that polygyny leads to a few males monopolizing all females leads to intense competition between males, which favors the evolution of larger males that can better deal with their rivals. [10 Greatest Mysteries of the First Humans]

"For me, the most important implication is that the area might harbor more ichnofossils— knowledge that could be used to solve many problems regarding different aspects of hominins," said lead study author Fidelis Masao, a palaeolithic archaeologist at the University of Dar es Salaam in Tanzania.

The new sets of footprints belong to two individuals, and were discovered at a place now dubbed "site S," located about 490 feet (150 meters) south of the prints discovered in 1978. Surrounded by dozens of other animal footprints — such as those belonging to a rhino, a giraffe, some horses and guinea fowl — along with raindrop impressions, the new tracks were apparently made on the same surface at the same time, and went in the same direction and at a similar speed as the A. afarensis prints found in 1978. Back when this ancient hominin was alive, the landscape was a bit like it is today — a mix of bushland, woodland and grassland with a nearby forest along the river.

Masao said that, after they had discovered the new footprints, one of the local Maasai workers said to him,"in not too good Swahili, 'Masao umepata choo.'" The worker meant to say, "Masao, you have become famous," but the Swahili word for "famous"is "cheo," not "choo," Masao explained.

"The latter means 'toilet' or 'poop,'" Masao said.

Judging by the impressions each foot made in the earth and the distance between each track, the researchers could estimate the size and weight of the individuals who made each set of prints. One individual was likely male, about 5 feet 5 inches (1.65 m) tall and 98.5 lbs. (44.7 kilograms). The other was likely female, about 4 feet 10 inches (1.46 m) tall and 87 lbs. (39.5 kg), the researchers said. [In Photos: 'Little Foot' Human Ancestor Walked With Lucy] 

The estimates from the new male exceed the estimated height and weight of the tallest previous specimen from Laetoli by more than 7.8 inches (20 cm) and 13.2 lbs. (6 kg). Indeed, the estimated size of the new male individual "makes him the largest Australopithecus afarensis specimen identified so far," said senior study author Giorgio Manzi, a paleoanthropologist at Sapienza University in Rome.

Study co-author Marco Cherin, a vertebrate paleontologist at the University of Perugia in Italy, noted that he and some of the other researchers walked barefoot at the site to avoid damaging the tracks. "We realized that the feet of many of us fit well with the footprints," Cherin told Live Science.

Similarly, the new female is an estimated 1.2 to 1.6 inches (3 to 4 cm) taller than previous female specimens from Laetoli, the researchers said. This new female is also more than 11.8 inches (30 cm) taller than Lucy.

When these new prints are considered together with the prints discovered in 1978, it suggests "several early bipedal hominids moving as a group through the landscape, after a volcanic eruption and a subsequent rainfall," Manzi told Live Science.

One tentative conclusion from these findings is that the group might have consisted of "one male, two or three females, and one or two juveniles," Manzi said. This idea, in turn, potentially suggests that this male — and, therefore, other males in the species — may have had more than one female mate, Cherin said. However, Cherin did caution that "the inferences on sexual dimorphism [differences between the sexes] and on social structure need to be evaluated carefully."

These findings suggest that sexual dimorphism may have been much more pronounced and certain in A. afarensis than scientists had thought. Prior work found that high sexual dimorphism is linked with polygyny — for example, in gorillas. In contrast, humans and their closest living relatives, chimpanzees and bonobos, are only moderately sexually dimorphic.

Scientists have hotly debated the level of sexual dimorphism in A. afarensis for nearly 40 years, "with some researchers supporting the notion of an only moderate degree of dimorphism, not too different from Homo sapiens, while the rest of the world supports the idea of marked sexual dimorphism," Cherin said. Their findings are "strong evidence that this fossil hominin was characterized by a strong variation in size."

Future research will aim to excavate more tracks from Laetoli to learn more about how these ancient relatives of humanity walked, Cherin said.

The authors of this new study "should be applauded for their efforts and the exciting but preliminary results," Jungers told Live Science. "There is much more analytical work to be done. I'm sure the authors would agree and look forward to the 'next steps' in their research program."

Masao, Cherin, Manzi and their colleagues detailed their findings online Dec. 14 in the journal eLife.

Original article on Live Science.