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Ancient burial site in Belize reveals when people started eating maize



June 3 (UPI) — Maize is a staple crop across much of the Americas, and new research suggests it’s been that way for at least 4,700 years.

Reconstructing the diets of early human populations in tropical regions like Central America has proven quite difficult, but scientists recently discovered a burial site in present-day Belize that has been continuously used for over 10,000 years.

Given the shallow nature of most graves and burial sites, it’s rare for human remains to end up layered sequentially — let alone a burial site featuring well-preserved remains.

“Finding intact burials from any time period is rare in tropical environments as the high temperatures and humidity are favorable to bacteria and other decomposers,” archaeologist Mark Robinson, a postdoctoral research fellow at Exeter University in Britain, told UPI in an email. “The rock shelters we excavated just happen to have the perfect set of factors to protect from the elements, creating a very dry, loose sediment, with no tree roots disturbing the interred bones.”

To find out when humans that frequented the two rock shelters first started eating maize, scientists analyzed bones from 44 human skeletons.

“The food we consume is absorbed and builds our body’s tissues,” Robinson said. “The chemical signature of that food leaves its mark in our bodies, meaning we really are what we eat.”

Because maize photosynthesizes differently than other kinds of plants, it leaves a unique chemical signature in bones.

“Maize, in the grass family of plants, creates a different carbon signature than the fruit, nuts, and leafy greens we consume from trees and herbs,” Robinson said.

The oldest remains that researchers recovered from the burial site were dated to between 9,600 and 8,600 years ago. Humans continued to bury the dead at the rock shelters until just 1,000 years ago. The isotopic ratios measured in the ancient bones showed humans in Central America began eating maize nearly 5,000 years ago.

Prior to the introduction of maize, humans in the region relied on herbs, fruits and nuts from local trees and shrubs, as well as with meat from hunting native land animals. Isotopic analysis of the bones of two infants suggests their mothers were eating large amounts of maize by at least 4,700 years ago.

As early as 4,000 years ago, maize made up nearly 70 percent of the diets of some people in Central America.

By the time the first European explorers arrived in the Americas, corn was ubiquitous among native populations. The new study — published Wednesday in the journal Science Advances — can help researchers reconstruct the growing importance of maize among native populations.

“Decades of research has revealed the importance of the crop for cultural identity, cosmological beliefs, creation myths, landscape management, the economy, as well as dietary nutrition,” Robinson said.

“Although the impact and importance of maize has been extensively researched, how, why and when maize was domesticated and adopted by so many diverse groups is still little understood,” he said. “The data from these contexts enables us for the first time to chronologically explore these questions in a single location.”

As the new analysis revealed, what began as a supplemental food source slowly became more important over several generations.

“Farmers would have to learn how to cultivate the crop and make the decision to increase the labor investment into its cultivation, becoming more reliant on the grain at the expense of other sources of nutrition,” Robinson said.

“By the later periods, whole socioeconomic systems were built around maize agriculture, with landscapes transformed to maximize cultivation,” Robinson said. “These data provide the first lines of evidence for how that adoption process took place and how long it took.”

The latest isotopic analysis can provide context to the archaeological remains of early Central American settlements. The adoption of corn as a staple diet was closely intertwined with the development of farming tools and food processing technologies, as was the evolution of local economies and social and political structures.

By the time the Mayan civilization emerged some 2,000 years ago, maize wasn’t just a source of calories, it was a crop of tremendous importance — culturally, economically and politically.

“We are currently analyzing genomic data from the skeletal material, which will provide new insight into who these people were,” Robinson said. “This will help us unravel the process of adoption of the technology. Did a new population enter the area, bringing maize agriculture, or were the seeds and plants passed between communities.”

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NASA’s OSIRIS-REx touches down on asteroid Bennu to nab sample



Oct. 20 (UPI) — NASA’s OSIRIS-REx touched down on asteroid Bennu on Tuesday evening in a mission to scoop a sample of rocks and dirt.

The spacecraft — the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer — made soft contact with the asteroid at 6:12 p.m. EDT.

The historic “touch and go” event featured animation displaying OSIRIS-REx’s sample collection activities in real time. It takes time for real images of the touchdown to travel back to the Earth, so they won’t be released to the public until Wednesday.

The craft executed a series of maneuvers over the course of several hours before making soft contact with the surface of the asteroid to collect regolith, or rocks and dirt.

“It will be four and a half hours of anxiousness,” Beth Buck, OSIRIS-REx mission operations manager at Lockheed Martin Space, said in a news conference ahead of the event.

Buck made a comparison to the descent of a spacecraft on Mars, when there is typically “seven minutes of terror.”

The goal is to learn more about the solar system’s history and help “planetary defense” engineers with missions to protect earth from rogue asteroids. Bennu is believed to be a window into the solar system’s past since it’s a pristine, carbon-rich body carrying building blocks of both planets and life.

At around 1:50 p.m. EDT, the spacecraft left orbit around the asteroid before executing a series of burns to position itself over a sampling area nicknamed Nightingale.

Once in position, the craft began its approach to the asteroid at 5:50 p.m. EDT. It then spent about 15 seconds attempting to collect the regolith sample before backing away again.

The area, which is 52 feet in diameter, will make for a more demanding landing than expected, Kenneth Getzandanner, OSIRIS-REx flight dynamics manager at the NASA Goddard Space Flight Center in Maryland, said in the news conference.

The original mission called for a landing “zone” about 150% larger than Nightingale, at 82 feet, but that changed because Bennu was more rocky than expected.

The goal was to collect at least 1.7 ounces of fine-grained material, but the spacecraft can carry up to 4.4 pounds, Heather Enos, OSIRIS-REx deputy principal investigator at the University of Arizona said.

“I would love for that capsule to be completely full,” Enos said.

Though early images from the asteroid should hint at whether the mission succeeded, it will take engineers roughly 10 days to compare and analyze the mass before and after the maneuver to actually know how much dirt is inside the OSIRIS-REx.

If it failed, the spacecraft has enough fuel to attempt two more touch downs to collect material.

The spacecraft is expected to return to Earth, with the regolith sample from Bennu, in 2023.

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SpaceX scrubs Starlink launch until Thursday, if weather cooperates



Oct. 21 (UPI) — Just three days after sending 60 more Starlink satellites into orbit, SpaceX is aiming to launch another batch of broadband satellites into space from Florida.

If the weather cooperates, Thursday’s launch will be SpaceX’s 15th Starlink mission.

Liftoff had been scheduled for 12:29 p.m. EDT Wednesday aboard a Falcon 9 rocket at Launch Complex 40 at Cape Canaveral Air Force Station, but controllers scrubbed the launch due to weather and rescheduled for 12:14 p.m. on Thursday.

With a launch Sunday, SpaceX increased the size of their Starlink constellation to nearly 800 satellites. The 15th mission will see another 60-odd satellites join the network.

“The goal of Starlink is to create a network that will help provide Internet services to those who are not yet connected, and to provide reliable and affordable Internet across the globe,” according to the Kennedy Space Center.

Weather for Wednesday’s planned launch had looked so-so and the Space Force’s 45th Weather Squadron predicted a 60 percent chance of favorable conditions.

“A mid-level inverted trough and associated easterly wave currently across the Bahamas will meander into the state over the next few days, bringing enhanced moisture, cloud cover, and instability with a higher coverage of showers and storms,” Space Force forecasters wrote.

They said Thursday’s forecast looks quite similar to Wednesday’s.

Earlier this month, SpaceX founder and CEO Elon Musk tweeted that Starlink’s constellation was big enough to begin beta-testing the Internet service system in both the United States and southern Canada.

SpaceX has already offered Starlink Internet services to emergency responders in wildfire-stricken areas of Washington State.

Washington’s Hoh tribe is also using the Internet service to provide their members online education and telehealth services.

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Chernobyl-level radiation harms bumblebee reproduction



Oct. 21 (UPI) — Bees are more sensitive to radiation than scientists thought. Scientists found the reproduction rates of bumblebees declined significantly when exposed to Chernobyl-level radiation.

The research, published Wednesday in the journal Proceedings of the Royal Society B: Biological Sciences, suggests radiation in Ukraine’s Chernobyl Exclusion Zone could impair pollination services, triggering wider ecological consequences than previously estimated.

Humans are not allowed to live in the Chernobyl Exclusion Zone, the disaster area more directly impacted by the 1986 nuclear accident, the worst in history. However, the destroyed nuclear reactors are surrounded by forests that are populated by robust populations of birds, bears, bison, lynx, moose, wolves and more.

Efforts to gauge the effects of radiation contamination on insects have yielded mixed results in the past. While some studies have suggested insects are relatively radiation-resistant, others have demonstrated significant impairment.

When researchers exposed bumblebees in the lab to radiation dose of 100 µGyh-1, an amount approximating exposure inside the Chernobyl Exclusion Zone, reproduction rates among the bees dropped between 30 and 45 percent.

Researchers found a direct correlation between the size of the radiation dose and reproduction rate declines. Lower levels of radiation had a smaller effect, while larger doses yielded greater declines.

Scientists were surprised to find they were able to detect reproductive rate declines at very small levels of radiation exposure.

“Our research provides much needed understanding as to the effects of radiation in highly contaminated areas and this is the first research to underpin the international recommendation for the effects of radiation on bees,” lead study author Katherine Raines, environmental scientist at the University of Stirling in Scotland, said in a news release.

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