Science

Scientists have found that human beings age at a molecular level in two accelerated bursts – first at the age of 44, and then again at 60.

In a study published in the journal Nature Aging, scientists at Stanford University and Nanyang Technological University in Singapore followed 108 participants over several years to observe aging changes in their molecules — RNA, proteins and participants’ microbiomes.

The scientists found that human aging does not happen in a gradual, linear way. Rather, the majority of the molecules they studied showed accelerated, non-linear changes at the ages of 44 and 60.

Xiaotao Shen, an assistant professor in microbiome medicine at Nanyang Technological University and first author of the study, told CNN that the results show “we are not becoming old gradually.” Some points in time are particularly important for our aging and health, he added.

For example, the ability to metabolize caffeine notably decreases – first around the age of 40 and once more around 60. Components involved in metabolizing alcohol also diminish, particularly around the age of 40, Michael Snyder, chair of the department of genetics at Stanford and an author of the study, told CNN, referring to the two waves of aging.

Snyder added that, anecdotally, “people often get muscle injuries and see their fat accumulation hit in their 40s (related to lipid metabolism), and definitely sarcopenia (muscle loss) hit people in their 60s — this is a very big deal.”

Generation X and millennials face a higher risk of getting certain types of cancer when compared to earlier generations, according to a large new study published Wednesday.

In the study, published in the Lancet Public Health journal, researchers from the American Cancer Society (ACS) studied 34 of the most common cancers. They found that cancer incidence rates continued to rise in progressively younger generations in 17 of the cancers, including breast, pancreatic and gastric cancers.

For eight of the 17 cancers, researchers found that cancer incidence rates rose for each successive birth cohort since 1920. For nine of them, incidence rates increased in younger cohorts, after first declining in older birth cohorts.

“These findings add to growing evidence of increased cancer risk in post-Baby Boomer generations, expanding on previous findings of early-onset colorectal cancer and a few obesity-associated cancers to encompass a broader range of cancer types,” Hyuna Sung, lead author of the study, said in a statement.

The study highlighted the need to identify and address the “underlying risk factors in Gen X and Millennial populations” to explain and address these rising cancer rates in younger generations, said Ahmedin Jemal, a senior author of the study.

“Birth cohorts, groups of people classified by their birth year, share unique social, economic, political, and climate environments, which affect their exposure to cancer risk factors during their crucial developmental years,” Sung added.

An international team of scientists has studied 33 years of satellite data and found that Earth is actually getting significantly greener as a result of rising carbon dioxide levels, with greater carbon emissions over the past three decades leading to a huge increase in the amount of leaves on plants and trees.

"We were able to tie the greening largely to the fertilising effect of rising atmospheric CO2 concentration by tasking several computer models to mimic plant growth observed in the satellite data," said researcher Ranga Myneni from Boston University.

But how are airborne pollutants spurring vegetation growth? The process, called the carbon fertilisation effect, results from leaves absorbing CO2 from the air as part of photosynthesis. With greater levels of carbon in the atmosphere, plants and trees and even crops actually grow faster, particularly in warm climates.

And with the levels of carbon in the atmosphere as high as they are now, that's seen a massive increase in the amount of vegetation over the surface of the planet.

"The greening over the past 33 years reported in this study is equivalent to adding a green continent about two times the size of mainland USA (18 million km2), and has the ability to fundamentally change the cycling of water and carbon in the climate system," said one of the team, Zaichun Zhu from Peking University in China.

As a result of the growth in recent decades, vegetation now covers almost a third (32 percent) of the planet's total surface area, occupying about 85 percent of all ice-free land.

But while extra greenery – and its ability to absorb atmospheric carbon – sounds like a positive for the environment, the scientists warn that this side effect of high carbon levels will only be temporary, and won't ultimately help against other consequences of climate change, such as severe weather, and rising temperatures and sea levels.

"[S]tudies have shown that plants acclimatise, or adjust, to rising CO2 concentration and the fertilisation effect diminishes over time," said Philippe Ciais from the Laboratory of Climate and Environmental Sciences in France.

Nor is CO2 the only factor behind the current green trends. The scientists say nitrogen use in agricultural fertilisers, climate change generally, and land management also contribute to the phenomenon in lesser amounts.

Wild sharks off the coast of Brazil have tested positive for cocaine, according to new study by Brazilian scientists, in the latest research to demonstrate how illegal drug consumption by humans is harming marine life.

According to a study entitled Cocaine Shark and published in the journal Science of the Total Environment, scientists dissected the bodies of 13 sharpnose sharks (Rhizoprionodon lalandii) caught in fishermen’s nets off a beach in Rio de Janeiro.

All 13 tested positive for the drug.

Previous studies have found cocaine in river, sea and sewage water, and traces of the drug have been found in other sea creatures such as shrimps.

A separate study recently revealed that high levels of cocaine residue were causing “serious toxicological effects” in animals such as brown mussels, oysters and eels in Santos Bay, in the Brazilian state of São Paulo.

But the concentration found in the Rio sharks was 100 times higher than had been found in other marine animals, the researchers said.

How the cocaine ended up in the sharks remains a mystery.

You can't disprove flat earth theory... or can you?

In his 11 years studying ant behavior, biologist Erik Frank had never seen anything like it. He and his colleagues at the University of Würzburg brought Florida carpenter ants back to their lab in Germany to learn how they respond to injury. Most ant species treat the injured or severed limb of a comrade by coating it with an antimicrobial goo. But the reddish-brown carpenter ants took a different tack: They bit the remainder of the limb off, effectively amputating it.

Other animals, such as lizards, shed their own limbs to escape predators, but Frank says this is the first case of an insect severing the leg of a nestmate to save its life. The only other species that does this is humans. “I didn’t believe this at all because it was very counterintuitive,” he says. “I repeated the experiment four times before I accepted it.”

The United States has been rocked by an extraordinary number of tornadoes and devastating storms this year that have already left a staggering price tag.

Now heading into what forecasters say will be an extreme summer – from punishing heat waves to severe weather and hurricanes – the nation’s disaster relief agency is expected to run out of money before it’s even over.

The US has been thrashed with 11 extreme weather disasters with costs exceeding $1 billion so far this year, with a total price tag of $25.1 billion, according to an updated tally from the National Oceanic and Atmospheric Administration. It’s tied for the second-most such disasters on record and doesn’t even include the extreme weather in the second half of May, said Adam Smith, an applied climatologist with NOAA.

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FEMA’s tenuous balance sheet reflects how many destructive storms have already lashed the US.

This spring produced the second-most tornadoes to-date since records began in 1950, according to the Storm Prediction Center. Tornado activity skyrocketed from late April through May, with more than 780 confirmed tornadoes cutting across the central and eastern US during April and May, the SPC said.

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A chorus of expert voices are calling for an above-average Atlantic hurricane season as anxiety-inducing conditions in the atmosphere and oceans align. Record-breaking ocean heat is expected to feed hurricanes, helping them form, strengthen and survive. El Niño is predicted to give way to La Niña and create more favorable atmospheric conditions for storms to thrive.

Just about every kind of extreme weather is possible during summer, including more severe thunderstorms. June is the third-most active month for tornadoes in the US, according to the SPC. It’s also the most-active month for destructive and costly severe hail, a 2012 study found.

Lots of animals communicate with each other, from tiny mice to enormous whales. But none of those forms of communication share even a small fraction of the richness of human language. Still, finding new examples of complex communications can tell us things about the evolution of language and what cognitive capabilities are needed for it.

On Monday, researchers reported what may be the first instance of a human-like language ability in another species. They have evidence that suggests that elephants refer to each other by individual names, and the elephant being referred to recognizes when it's being mentioned. The work could benefit from replication with a larger population and number of calls, but the finding is consistent with what we know about the sophisticated social interactions of these creatures.

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he researcher worked with recordings of elephant calls made in three distinct social contexts. One was a contact call, made when a group member is far enough away that they are no longer visible and was used to re-establish contact. A second is greeting calls, which are made when an individual approaches another. And the third was a caregiving call given to young offspring within the group. Calls were used for analysis if the researchers could clearly identify a recipient of the call.

The rumbles elephants produce are harmonically complex, and it's difficult to identify important features by looking over things like frequency plots. So, the researchers used two methods of examining them. One was a machine-learning approach called a random forest model that can be used for classification tasks. Separately, they used audio analysis software to identify the degree to which any two calls share common features.

Once the system was set up, it correctly identified the recipient in over a quarter of the calls analyzed, much higher than would be expected based on random chance. That may seem low, but recall that it may not always be necessary to call out an individual's name each time you communicate with them.

The researchers also analyzed calls from one individual directed toward another. They had higher levels of similarity to each other than they did to any calls to different individuals. This was true regardless of social relationships among the individuals or the context in which the call was being made. Social context also mattered as it was easier to detect names in contact and caregiving contexts.

Beachgoers in the Gulf Coast of Florida have been told to be vigilant, after three swimmers were attacked by sharks in two separate attacks.

One woman was said to have had part of her arm amputated after being bitten on Friday in Walton County in north-west Florida.

Less than two hours later, at another beach four miles further east, two teenage girls were in waist-deep water with friends when they were attacked.

One of the girls suffered "significant injuries to the upper leg and one hand" while the other had minor injuries on one of her feet, fire officials said.

"The Pill" may be negatively impacting and altering women's mental lives.

The authors of that study explained how hormonal birth control appears to shrink an important region of the brain, the ventromedial prefrontal cortex, that’s associated with fear and emotional processing more broadly.

In our study, we show that healthy women currently using COCs had a thinner ventromedial prefrontal cortex than men.

This part of the prefrontal cortex is thought to sustain emotion regulation, such as decreasing fear signals in the context of a safe situation. Our result may represent a mechanism by which COCs could impair emotion regulation in women.

What the researchers found was that the ventromedial prefrontal cortex in women who were currently using COCs was significantly thinner compared to men.

Interestingly, this reduced thickness was not observed in women who had discontinued use of COCs in the past. This suggests that the behavioural changes may be reversible if use of the Pill ceases.

The possibility that this thinning effect might be reversible is the only potential silver lining to this study, which otherwise suggests that the Pill really may be having profound effects on the behaviour of the tens of millions of women—and hundreds of millions worldwide—who take it.