Maybe it starts off feeling low energy, or maybe you get a little cranky. You may have a headache or difficulty concentrating. Your brain is sending you a message: you are hungry. Find food.

Studies in mice have identified clusters of cells called AgRP neurons near the bottom of the brain that can cause this nasty feeling of hunger. even “hungry”, feeling. They are close to the blood supply to the brain, which gives them access to hormones from the stomach and adipose tissue that indicate energy levels. When energy is low, they act on many other areas of the brain to stimulate nutrition.

By eavesdropping on AgRP neurons in mice, scientists began to understand how these cells turn on and prompt animals to seek food when they lack nutrients, and how they feel it. entry of food into the intestines The researchers also found that the activity of AgRP neurons is impaired in mice with symptoms similar to those of anorexia, and that activation of these neurons can help restore normal eating patterns in these animals.

Understanding and manipulating AgRP neurons could lead to new treatments for both anorexia and binge eating. “If we could control this feeling of hunger, we could have better control over our diet,” says Amber Alhadeff, a neuroscientist at the Monell Chemical Senses Center in Philadelphia.

To eat or not to eat

AgRP neurons appear to play a key role in appetite: their deactivation in adult mice causes the animals to stop eating – they can even starvation. Conversely, when the researchers fire the neurons, the mice jump into the food bowls and overeat.

Experiments in several laboratories in 2015 helped illustrate what AgRP neurons do. The researchers found that when mice ran out of food, AgRP neurons shot more often. But the sight or smell of food alone—especially something savory like peanut butter or Hershey Kiss—was enough to Relax this activity, within a few seconds. From this, the scientists concluded that AgRP neurons make animals look for food. Once food is found, they stop shooting as hard.

One research team, led by neuroscientist Scott Sternson at the Genelia Research Campus in Ashburn, Virginia, also showed that the activity of AgRP neurons appears to make mice feel bad. To demonstrate this, the scientists designed mice so that AgRP neurons would fire when light hit the brain through an optical fiber (the fiber still allowed the mice to move freely). They placed these engineered mice in a box with two distinct areas: one painted black with a plastic slatted bottom, and the other white with a soft tissue paper floor. If the researchers activated the AgRP neurons whenever the mice entered one of the two areas, the mice began to avoid that area.

Sternson, now at UC San Diego, concluded that AgRP activation felt “slightly uncomfortable.” He says this makes sense in nature: every time a mouse leaves its nest, it is at risk from predators, but it must overcome that fear in order to forage and eat. “These AgRP neurons are kind of a push that in a dangerous environment you’re going to look for food to stay alive.”

A 2015 study by Sternson found that while the sight or smell of food quiets the AgRP neurons, it is temporary: activity resumes immediately if the mouse cannot make it to the end and eat the snack. With more experimentation, Alhadeff and colleagues found that something that turns off AgRP neurons is more reliable. Calories enter the intestines.

This article is from Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

In 1985, the British Antarctic Survey warned the world that a giant hole was forming in the atmosphere high above the South Pole in the Earth’s protective ozone layer. World leaders quickly gathered to work out a solution. Two years later, the United Nations agreed to ban chemicals that erode the layer of the stratosphere that protects the Earth from solar ultraviolet radiation. Known as the Montreal Protocol Agreement, it is still one of the most widely ratified UN treaties.

The Montreal Protocol was a victory for diplomacy and the stratosphere. But the agreement, unknown to its signatories at the time, also came as an unexpected hedge against climate catastrophe. ace new study reveals that the aptly named ozone-depleting substances (ODSs) that created the hole over Antarctica are also responsible for the 30 percent temperature rise we observed worldwide from 1955 to 2005.

Michael Sigmond, a climate scientist at Environment and Climate Change Canada, is the lead author of a new study that calculates the ability of ODS to capture greenhouse gases. The contribution of substances to global warming, he says, is “greater than most people realize.”

The Montreal Protocol governs almost 100 ozone-eating chemicals. Many of these are related to chlorofluorocarbons (CFCs), chemicals popularized in the 1930s for use in aerosol cans, foam plastics, and refrigerators. Compared to the many toxic and flammable alternatives they replaced, CFCs were considered miracle chemicals, and by the early 1970s the world was producing almost a million tons of them a year.

CFCs are inert and therefore do not react with other gases. Instead, they tend to accumulate in the atmosphere and drift where the wind takes them, hanging in the air for long periods of time. 85 years old or more. Once they reach the stratosphere, the second layer of the Earth’s multi-layered atmosphere, the CFCs begin to break down. They are “destroyed by photons,” explains Dennis Hartmann, a climate scientist at the University of Washington who was not involved in the study. This jet noise caused a hole in the ozone layer.

In the troposphere, the lowest level of the atmosphere where fewer photons reach, ODSs act as persistent greenhouse gases. Back in 1987, scientists knew that ODSs captured some solar radiation, but didn’t know how much. Only recently Scientists are gathering evidence that ODSs are, in fact, one of the most destructive warming agents of the past half century.

The effects of this warming are intensifying at the poles. The work of Zsigmond and colleagues shows that if ODS had never been mass-produced—if atmospheric concentrations had remained at 1955 levels—the Arctic today would be at least 55% colder and there would be 45% more sea ice. September.

ODS production stabilized in the 1990s. But because they are so long-lived, these gases are still circulating, and the warming they cause continues to increase. But it could have been much worse. By banning ODS, the Montreal Protocol inadvertently prevented 1°C warming by 2050.

With the Montreal Protocol, world leaders rallied around an urgent matter. In the process, we inadvertently abandoned the second largest factor in global warming. The windfall benefits for the global climate, says Suzanne Tegtmeier, an atmospheric scientist at the University of Saskatchewan who was not involved in the study, “could be considered a very welcome and very positive side effect.”

While it has taken a lot more negotiation and innovation to start displacing the main driver of climate change, carbon dioxide, the Montreal Protocol proves the power of collective action and shows how addressing environmental challenges can help us in ways we didn’t expect.

This article is from Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

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Naturalist Chris Packham won a libel suit against a website that claimed it was misleading people into donating to a tiger charity.

The presenter filed a lawsuit in the High Court over articles published on the Country Squire Magazine website.

The site’s editor Dominic Wightman, writer Nigel Bean, and proofreader Paul Reid defended the libel suit.

Mr. Justice Saini ruled in favor of Mr. Packham against Mr. Whiteman and Mr. Bean, but rejected the decision against Mr. Reid.

Mr Whiteman and Mr Bean were ordered to pay £90,000 in damages to the owner of the Springwatch.

“Mr Packham did not commit any fraudulent or dishonest act,” the judge said in his 58-page decision.

“Mr Packham did not lie, and every statement he made was made with sincere faith in its truth.

“There was no fraud on his part in compiling the fundraising applications.”

During the trial, Mr. Packham said he was targeted because of his “deeply held views” on blood sports.

The 61-year-old man and his partner Charlotte Corney are trustees of an Isle of Wight shelter called the Wildheart Trust.

Mr Packham was accused of dishonestly raising money at the start of the Covid-19 pandemic, knowing the charity was to receive a £500,000 benefit from its insurance.

But Mr. Justice Saini said Mr. Whiteman and Mr. Bean “didn’t even come close to establishing the essential truth.”

“Instead of approaching the task with an investigative mind, these defendants targeted Mr. Packham as the person they had plans against,” he said.

He added: “Any investigative journalism quickly gave way to … an increasingly exaggerated and vitriolic vilification of Mr. Packham with unsubstantiated allegations of dishonesty in relation to peat burning and trust insurance.”

Testifying during the trial, Mr Packham explained: “We didn’t expect to be immune from Covid-19 shutdowns.”

He said the insurance payouts “ultimately saved the shelter in a time of dire need.”

The story goes on

“But to be very clear, if we hadn’t started the fundraising appeal as quickly as we did, these payments might have come in too late to make a difference,” he said.

Host’s house in the New Forest became a victim of arson and had dead animals were repeatedly left outside.

He said the defendants’ allegations were “misleading, agitated and inflamed by vociferous and violent conspirators who are increasingly publishing threatening and nefarious material about me and my family.”

Mr Packham added: “I go walking my dogs in the woods and I think, ‘Is today the day that a psychopath, fueled by all this hate, will come along and kill me?’

“I really don’t expect to live a long life without violence and intimidation anymore, because it only takes one wrong person to read Country Squire Magazine and everything goes horribly wrong.”

During the trial, Mr. Wightman and Mr. Bean’s attorney argued that the articles were true and in the public interest.

Mr. Reed’s lawyer called him “a mere proofreader” and was not responsible for the articles.

“Frank vitriol”

The judge agreed that Mr. Reid “shall not be editorially or similarly responsible for the impugned statements or the decision to publish them.”

But he said others “used the lawsuit as a way to present offensive material to vilify Mr. Packham.”

He added: “The tone sank to ominous threats and outright sarcasm, including offensive references to Mr. Packham’s neurodiversity and insults to (lawyers) Lee Day.

“This was not the result of any act of responsible journalism.”

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