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August 7, 2025

A toxicologist’s guide to poison ivy’s itch and bee stings’ burning pain – 2 examples of nature’s chemical warfare

Source: The Conversation – USA (3) – By Christopher P. Holstege, Professor of Emergency Medicine and Pediatrics, University of Virginia

There’s a lot to explore out there. aldomurillo/E+ via Getty Images

Enjoying the outdoors carries the danger of running into nature’s less-friendly side: toxic plants and animals.

As toxicologists at the University of Virginia’s Blue Ridge Poison Center, we see many patients each year suffering from itchy rashes from poison ivy and stings from wasps or bees.

Plants and animals deploy toxins most often in order to defend themselves. Learning how they do that and what happens when the human body is exposed to these substances can offer insights on how to prevent or manage these encounters with nature.

The goal is not to scare people away from the outdoors, but to equip them with the knowledge to appreciate these organisms’ intricate self-preservation strategies and to protect themselves in return.

Poison ivy, a ubiquitous source of itch

Whether in a remote state park or on a city playground, most people have encountered poison ivy. This plant is recognizable by its characteristic arrangement of leaves growing in groups of three with edges that vary from smooth to jagged. It can take many forms: a single small plant, a mass of ground cover, a small bush, or a climbing vine reaching many feet up a tree or building.

Poison ivy with big leaves growing on a tree — Poison ivy contains an oily chemical called urushiol that most people are allergic to.
Chris Light via Wikimedia Commons, CC BY

Poison ivy – its scientific name is Toxicodendron radicans – and its close relatives poison oak and poison sumac contain an oily substance called urushiol. This chemical is found in every part of the plant: the leaves, roots, stems and even the small white berries it produces in late summer.

About 75% of people will develop an allergic reaction on contact with urushiol. Urushiol has antimicrobial properties, and scientists think its job in the poison ivy plant is to protect it from diseases.

Because it is so oily, urushiol spreads easily. It can transfer from the plant to your skin, clothes, garden tools or even your pets. Direct plant contact isn’t the only risk: If urushiol is on your clothing or a pet’s fur and your skin later brushes against it, you can develop the same rash as you’d get from directly touching the plant.

A white goat munches plants including poison ivy. — Goats happily munch poison ivy as part of their expansive vegetarian diet. Only people and perhaps some other primates are allergic to poison ivy.
Terry Donovan via flickr, CC BY

From plant to skin

Urushiol triggers a delayed allergic reaction. When the oil touches your skin, it binds to skin cells, changing their shape. A molecule called CD1a then clocks urushiol as a foreign substance, prompting the immune system to mount an attack on the cells – hence the rash.

The symptoms do not appear instantly; the rash usually appears 12 to 48 hours after exposure. It often starts as redness and itching, then develops into small bumps or fluid-filled blisters. The reaction can be mild or severe, depending on how sensitive you are and how much urushiol got on your skin.

The rash itself isn’t contagious. Fluid from the blisters doesn’t spread it. What spreads the rash to other areas of your body or to others is the urushiol lingering on your skin, clothing, tools or pets. Once the oil is adequately washed away, the rash can’t spread to other people or to other areas of your body.

If you have touched poison ivy, wash the area as soon as you can with soap and water and change your clothes if possible. After that, the rash will eventually resolve on its own. You can help alleviate symptoms by using a topical steroid or anti-itch cream on the rash. In severe cases, or if the face is affected, patients may require oral steroids to treat the symptoms.

Bees and wasps: Home defenders

Bees and wasps are most active in the late summer. Because of this, we receive more frequent poison center calls about them during this season.

A bee sitting on a red and yellow flower — Stinging is how bees protect themselves and their hives from predators and attackers.
Ionenlaser via Wikimedia Commons, CC BY

Bees and wasps generally sting to defend their hives or nests or to protect themselves from perceived threats. They store venom in their abdominal sacs. When they sting, the venom flows through their stinger and is injected into their target’s skin.

This venom is a clear, slightly acidic liquid loaded with various active ingredients. For example, it contains enzymes such as phospholipase A2 that break down cell membranes, and peptides such as melittin that cause pain. The venom also contains natural chemicals such as histamine and epinephrine that affect blood vessels and the immune system.

Sting mechanics

Unlike with poison ivy, where the immune system’s reaction to the substance causes irritation, with bee and wasp stings it’s primarily the substance itself that causes pain – although immune response can still play a role. As soon as the venom enters a person’s skin, their body reacts.

A sharp, burning pain comes first as the components of the venom begin to inflict damage, followed by redness and then swelling of the area. Symptoms commonly peak within a few hours and fade within a day. However, some people have stronger reactions with larger areas of swelling that can last for several days. This is because everyone’s immune system is slightly different, and some people tend to have stronger reactions than others to foreign substances.

A closeup of a bee's stinger — A bee’s stinger is sharp and barbed, and it can continue to deliver venom for up to a minute if it remains stuck in your skin.
US Geological Survey via Wikimedia Commons

In rare cases, the immune system overreacts, releasing large amounts of histamine and other chemicals all at once. Histamine is most often released in response to a foreign substance, causing symptoms of an allergic reaction. This can lead to anaphylaxis, a severe allergic reaction that can make breathing difficult, lower blood pressure and cause airway swelling, and which can quickly become life-threatening.

Getting stung multiple times at once can also be life-threatening due to the sheer amount of venom injected, even in people without a bee venom allergy.

If you’re stung and the stinger is stuck in the skin, it should be removed immediately by the quickest means available. Bee stingers are barbed and can continue to deliver venom for up to a minute. Most bee or wasp stings require only symptomatic treatment, such as an over-the-counter steroid cream or oral antihistamine to reduce itching and swelling.

However, people who begin to develop more severe symptoms such as full body hives, vomiting or difficulty breathing should immediately seek emergency care. Anaphylactic reactions require rapid treatment with a medication called epinephrine and close monitoring in the hospital.

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

– ref. A toxicologist’s guide to poison ivy’s itch and bee stings’ burning pain – 2 examples of nature’s chemical warfare – https://theconversation.com/a-toxicologists-guide-to-poison-ivys-itch-and-bee-stings-burning-pain-2-examples-of-natures-chemical-warfare-261156

August 7, 2025

Vaccines hold tantalizing promise in the fight against dementia

Source: The Conversation – USA (3) – By Anand Kumar, Professor and Department Head of Psychiatry, University of Illinois Chicago

Researchers are in the earliest phase of piecing together how the shingles vaccine could play a role in lowering the risk of dementia. PM Images/DigitalVision via Getty Images

Over the past two centuries, vaccines have been critical for preventing infectious diseases. The World Health Organization estimates that vaccination prevents between 3 million and 5 million deaths annually from diseases like diphtheria, tetanus, influenza, measles and, more recently, COVID-19.

While there has long been broad scientific consensus that vaccines prevent or mitigate the spread of infections, there is new research suggesting that the therapeutic impact might go beyond the benefit of preventing infectious diseases.

An April 2025 study published in the prominent journal Nature found tantalizing evidence that the herpes zoster – or shingles – vaccine could lower the risk of dementia in the general population by as much as 20%.

We are a team of physician scientists with expertise in the clinical and basic science of neurodegenerative disorders and dementia.

We believe that this study potentially opens the door to other breakthroughs in understanding and treating dementia and other degenerative disorders of the brain.

A role for vaccines in reducing dementia risk?

One of the major challenges researchers face when trying to study the effects of vaccines is finding an unvaccinated “control group” for comparison – a group that is similar to the vaccine group in all respects, save for the fact that they haven’t received the active vaccine. That’s because it’s unethical to assign some patients to the control group and deprive them of vaccine protection against a disease such as shingles.

The Nature study took advantage of a policy change in Wales that went into effect in 2013, stating that people born on or after September 2, 1933, were eligible for the herpes zoster vaccination for at least a year, while those born before that cutoff date were not. The vaccine was administered to prevent shingles, a painful condition caused by the same virus that causes chickenpox, which can lie dormant in the body and be reactivated later in life.

The researchers used the policy change as a natural laboratory of sorts to study the effect of shingles vaccination on long-term health outcomes. In a statistically sophisticated analysis of health records, the team found that the vaccine reduced the probability of getting dementia by one-fifth over a seven-year period. This means that people who received the shingles vaccine were less likely to develop clinical dementia over the seven-year follow-up period, and women benefited more than men.

The study design allowed researchers to compare two groups without actively depriving any one group of access to vaccination. The two groups were also of comparable age and had similar medical comorbidities – meaning similar rates of other medical conditions such as diabetes or high blood pressure.

Results from this and other related studies raise the possibility that vaccines may have a broader role in experimental therapeutics outside the realm of infectious diseases.

These studies also raise provocative questions about how vaccines work and how our immune system can potentially prevent dementia.

How vaccines might be protective

One scientific explanation for the reduction of dementia by the herpes zoster vaccine could be the direct protection against the shingles virus, which may play a role in exacerbating dementia.

However, there is also the possibility that the vaccine may have conferred protection by activating the immune system and providing “trained immunity,” in which the immune system is strengthened by repeated exposure to vaccines or viruses.

The study did not differentiate between different types of dementia, such as dementia due to Alzheimer’s disease or dementia due to stroke. Additionally, researchers cannot draw any definitive conclusions about possible mechanisms for how the vaccines could be protective from an analysis of health records alone.

The next step would be a prospective, randomized, double-blind, placebo-controlled study – the “gold standard” for clinical trials in medicine – to directly examine how the herpes zoster vaccine compares with a placebo in their ability to reduce the risk of dementia over time. Such studies are necessary before any vaccines, as well as other potential therapies, can be recommended for routine clinical use in the prevention of dementia.

Brain image of early Alzheimer's disease — Randomized, placebo-controlled trials are needed in order to determine how the shingles vaccine compares with a placebo over time in protecting against dementia.
Peter Dazeley/Getty Images News

The challenges of untangling dementia

Dementia is a major noncommunicable disease that is a leading cause of death around the world.

A January 2025 study provided updated figures on lifetime dementia risk across different subsets of the U.S. population. The researchers estimate that the lifetime risk of dementia after age 55 is 42% – more than double earlier estimates. The dementia risk was 4% by age 75, and 20% by age 85, with the majority of risk occurring after 85. The researchers projected that the number of new cases of dementia in the U.S. would double over the next four decades from approximately 514,000 cases in 2020 to 1 million in 2060.

Once considered a disease largely confined to the developed world, the deleterious effects of dementia are now apparent throughout the globe, as life expectancy increases in many formerly developing countries. While there are different forms of dementia with varying clinical manifestations and underlying neurobiology, Alzheimer’s disease is the most common.

Prospective studies that specifically test how giving a vaccine changes the risk for future dementia may benefit from studying patient populations with specific types of dementia because each version of dementia might require distinct treatments.

Unfortunately, for the past two to three decades, the amyloid hypothesis of Alzheimer’s disease – which posits that accumulation of a protein called amyloid in the brain contributes to the disorder – dominated the scientific conversation. As a result, most of the efforts in the experimental therapeutics of Alzheimer’s disease have focused on drugs that lower the levels of amyloid in the brain.

However, results to date have been modest and disappointing. The two recently approved amyloid-lowering therapies have only a minimal impact on slowing the decline, are expensive and have potentially serious side effects. And no drug currently approved by the Food and Drug Administration for clinical use reverses the cognitive decline.

Studies based on health records suggest that past exposure to viruses increase the risk of dementia, while routine vaccines, including those against tetanus, diphtheria, pertussis, pneumonia, shingles and others, reduce the risk.

Innovation and an open mind

There is sometimes a tendency among scientists to cling to older, familiar models of disease and a reluctance to move in more unconventional directions.

Yet the process of doing science has a way of teaching researchers like us humility, opening our minds to new information, learning from our mistakes and going where that data takes us in our quest for effective, lifesaving therapies.

Vaccines may be one of those paths less traveled. It is an exciting possibility that may open the door to other breakthroughs in understanding and treating degenerative disorders of the brain.

Jalees Rehman receives funding from NIH.

Anand Kumar does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Vaccines hold tantalizing promise in the fight against dementia – https://theconversation.com/vaccines-hold-tantalizing-promise-in-the-fight-against-dementia-257807

August 7, 2025

This stone tool is over 1 million years old. How did its maker get to Sulawesi without a boat?

Source: The Conversation – Global Perspectives – By Adam Brumm, Professor of Archaeology, Griffith University

A stone tool from 1.04 million year ago. M.W. Moore/University of New England

Stone tools dating to at least 1.04 million years ago have been found on the Indonesian island of Sulawesi. This means early hominins made a major sea crossing from the Asian mainland much earlier than previously thought – and they likely didn’t have any boats.

This discovery, made by a team of Indonesian archaeologists working in collaboration with Australian researchers, is published today in Nature.

It adds to our understanding of how extinct humans once moved across the Wallace Line – an imaginary boundary that runs through the Lombok Strait in the Indonesian archipelago.

Beyond this line, unique and often peculiar animal species – including hominins – evolved in isolation.

Hominins in Wallacea

The oceanic island zone between the Asian and Australian landmasses is known as Wallacea.

Previously, archaeologists have found hominins lived here from at least 1.02 million years ago, thanks to discoveries of stone tools at Wolo Sege on the island of Flores. Meanwhile, tools dated to around 194,000 years ago have been found at Talepu on Sulawesi.

The human evolutionary story in the islands east of the Asian landmass is strange.

The ancient human species that used to live on the island of Flores were small in stature. We know this thanks to the fossils of Homo floresiensis (popularly known as “hobbits”), as well as the 700,000-year-old fossils of a similar small-bodied hominin.

These discoveries suggest it could have been the extinct Asian hominin Homo erectus that breached the formidable marine barrier between this small Wallacean island and mainland Southeast Asia. Over hundreds of thousands of years, their body size reduced in what’s known as island dwarfism.

To the north of Wallacea, the island of Luzon in the Philippines has also yielded evidence of hominins from around 700,000 years ago. Just recently, fossils of a previously unknown diminutive hominin species, Homo luzonensis, were found here.

So how and when did ancient human species cross the Wallace Line?

The Sulawesi stone tools

Our new study reveals the first evidence a sea crossing to Sulawesi may have happened at least 1 million years ago. That’s much earlier than previously known, and means humans reached here at about the same time as Flores, if not earlier.

A field team led by senior archaeologist Budianto Hakim from the National Research and Innovation Agency of Indonesia (BRIN), excavated a total of seven stone artefacts from the sedimentary layers of a sandstone outcrop in a modern corn field at Calio in southern Sulawesi.

In the Early Pleistocene, there was a river channel nearby. This would have been the site of hominin tool-making and other activities such as hunting.

The Calio artefacts consist of small, sharp-edged fragments of stones (flakes) that the early human tool-makers struck from larger pebbles they most likely found in nearby riverbeds.

To produce these flakes, the hominins hit the edge of one stone with another in a controlled manner. This would fracture the first stone in a predictable way.

This tool-making activity left telltale marks on the stones that can be clearly distinguished from naturally broken rocks. So we can say unequivocally that hominins were living in this landscape, making stone tools, at the time the ancient river sediments that comprise the sandstone rock were accumulating.

And that was a very long time ago. Indeed, the team confirmed an age of at least 1.04 million years for the stone artefacts based on paleomagnetic dating of the sandstone itself, along with direct dating of a pig fossil found alongside the artefacts.

A group of people on an archaeological dig under a blue shade cloth. — Excavations at the Early Pleistocene site of Calio in South Sulawesi, Indonesia.
BRIN

Who were these hominins and how did they get to Sulawesi?

As noted earlier, previous research has shown that archaic, stone tool-making hominins managed to get across from the Asian continental landmass to colonise at least some islands in Wallacea.

The discovery of the extremely old stone tools at Calio is another significant new piece of the puzzle. This site has yet to yield any hominin fossils, however. So while we now know there were tool-makers on Sulawesi 1 million years ago, their identity remains a mystery.

Indeed, there are many fascinating questions that remain unanswered, including how these hominins were able to cross the Wallace Line in the first place.

When sea levels were at their lowest, the shortest possible distance between Sulawesi and the nearest part of the adjacent Asian landmass would have been about 50 kilometres.

This is too far to swim, especially since the ocean currents are far too strong. It’s also unlikely these archaic hominins had the cognitive ability to develop watercraft capable of making sea voyages. Setting sail over the horizon to an unseen land would have required advanced planning to gather resources – something they probably weren’t capable of.

Most likely, then, they crossed to Sulawesi from the Asian mainland in the same way rodents and monkeys are suspected to have done – by accident. Perhaps they were castaways on natural “rafts” of floating vegetation.

Our discovery also leads us to wonder what might have happened to Homo erectus on the world’s 11th largest island. Sulawesi is more than 12 times the size of Flores, and much closer to the adjacent Asian mainland.

In fact, Sulawesi is a bit like a mini-continent in itself, which sets it apart from other Wallacean islands. If hominins were cut off in the ecologically rich habitats of this enormous island for a million years, would they have undergone the same evolutionary changes as the Flores hobbits? Or might something completely different have happened?

To unravel this fascinating story, we will continue to search the islands of Wallacea – especially those close to the Asian mainland – for ancient artefacts, fossils and other clues.

Adam Brumm receives funding from the Australian Research Council.

Basran Burhan is a researcher at Pusat Kolaborasi Riset Arkeologi Sulawesi (BRIN-Universitas Hasanuddin).

Gerrit (Gert) van den Bergh has received funding from the Australian Research Council.

Maxime Aubert receives funding from the Australian Research Council.

Renaud Joannes-Boyau receives funding from the Australian Research Council.

– ref. This stone tool is over 1 million years old. How did its maker get to Sulawesi without a boat? – https://theconversation.com/this-stone-tool-is-over-1-million-years-old-how-did-its-maker-get-to-sulawesi-without-a-boat-262337

August 7, 2025

Is Israel committing genocide in Gaza? We asked 5 legal and genocide experts how to interpret the violence

Source: The Conversation – Global Perspectives – By Melanie O’Brien, Associate Professor in International Law, The University of Western Australia

In January 2024, the International Court of Justice (ICJ) issued a provisional ruling in a case brought by South Africa against Israel, alleging genocide in Gaza. The court found Palestinians have a “plausible” right to protection from genocide in Gaza and that Israel must take all measures to prevent a genocide from occurring.

Since then, United Nations experts and human rights groups have concluded that Israel is committing genocide in Gaza. In recent weeks, others have done the same, including leading genocide scholars and two Israeli human rights groups.

While the ICJ case may take years to play out, we asked five Australian experts in international law and genocide studies what constitutes a genocide, what the legal standard is, and whether the evidence, in their view, shows one is occurring.

Melanie O’Brien is the president of the International Association of Genocide Scholars (IAGS). This piece does not represent the view of IAGS.

Ben Saul is the United Nations special rapporteur on human rights and counter-terrorism, an independent expert appointed by consensus of the member states of the United Nations Human Rights Council.

Eyal Mayroz served as a counterterrorism specialist with the Israeli Defence Forces in the 1980s.

Paul James and Shannon Bosch do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

– ref. Is Israel committing genocide in Gaza? We asked 5 legal and genocide experts how to interpret the violence – https://theconversation.com/is-israel-committing-genocide-in-gaza-we-asked-5-legal-and-genocide-experts-how-to-interpret-the-violence-262688

August 7, 2025

Climate-fuelled El Niño events are devastating butterflies, beetles and other tropical insects

Source: The Conversation – Global Perspectives – By Nigel Stork, Emeritus Professor in the Centre for Planetary Health and Food Security, Griffith University

Insects are arguably the most important animals on the planet. Their variety is unparalleled in nature, and they carry out vital tasks such as pollinating plants and providing food for other animals.

But all is not well in the insect world. Research over the last few years has shown sustained declines in insect species and numbers. It appeared Earth was witnessing a global-scale crash in insects – and climate change was partly to blame.

The evidence was mostly confined to temperate regions in the Northern Hemisphere. But our new research – published today in Nature – shows it’s also happening in the tropics, where most of Earth’s species live.

We found significant biodiversity loss in spiders, as well as insects including butterflies and beetles. The likely culprit is long-term changes to the El Niño cycle, caused by climate change. It suggests the life-support system underpinning the tropics is at serious risk in a warmer world.

Uncovering the effects of El Niño

El Niños vary massively across tropical regions, but are often characterised by hot and dry conditions (as opposed to the cool and moist conditions of La Niña).

Alternating El Niño and La Niña events can naturally cause many insects to come and go. That’s due to changes in temperature and moisture levels which can affect insect breeding, life cycles and behaviour.

But as climate change worsens, strong El Niño events are becoming more frequent and intense. We wanted to know how this affected insects in tropical regions.

To find out, we examined 80 existing studies of insects in relatively pristine tropical forests – mostly from the tropical Americas. We linked that data to measures of strength in El Niño and La Niña through time.

We found cause for concern. El Niño events appear to cause a rapid decline in both insect biodiversity, and the ecological tasks they perform. These trends were persistent and highly unnatural.

Several types of insects have become more rare in the tropical Americas over recent decades. These included butterflies, beetles and “true bugs” – insects from the order Hemiptera distinguished by two sets of wings and piercing mouthparts used to feed on plants. Butterflies in tropical Asia were also declining.

The strongest declines were in rare insects that would naturally decrease during El Niño. These insect populations would usually bounce back in a La Niña. But climate-fuelled El Niños are causing many populations to fall so far, they cannot recover.

Drastic changes to forests

Our findings suggest the diversity of tropical insects could be chipped away with every El Niño event. This is not just a problem for the species themselves, but other parts of the ecosystem that depend on them.

Our research also involved modelling the decomposition and consumption of leaves by insects across the tropical Americas, Asia and Africa. Both processes are crucial to the health of tropical forests.

Decomposition fluctuated in line with the abundance of termites, which are probably the most important decomposers in the tropics. And worryingly, the amount of live leaves consumed by insects appears to have crashed in recent decades. This correlated strongly with the crash in butterflies and beetles.

These drastic changes may have implications for food webs and other organisms that rely on insects.

a black beetle — The diversity of tropical insects could be chipped away with every El Niño event.
Li Ajang/Shtterstock

A difficult future ahead

Our research could not take in the huge diversity of tropical insects – most of which have not yet been formally described by scientists. But it points to a difficult future for insects – and their habitats – as climate change worsens.

Little data exists on insect numbers in Australia’s Wet Tropics, in Queensland. However, monitoring work is underway at facilities such as the Daintree Rainforest Observatory. Such projects will help us better understand changes in insect biodiversity under climate change.

More research is also needed at other locations around the world. Given the fundamental role insects play in supporting life on Earth, the urgency of this work cannot be overstated.

Nigel Stork receives funding from Australian Research Council grant DP200103100

Adam Sharp receives funding from Hong Kong University Grants Committee Collaborative Research Fund (C7048-22GF).

– ref. Climate-fuelled El Niño events are devastating butterflies, beetles and other tropical insects – https://theconversation.com/climate-fuelled-el-nino-events-are-devastating-butterflies-beetles-and-other-tropical-insects-262625

August 7, 2025

Why Sydney Sweeney’s American Eagle campaign is part of a wider cultural backlash

Source: The Conversation – Canada – By Meaghan Furlano, PhD Student, Sociology, Western University

Actress Sydney Sweeney is once again embroiled in controversy. This time the debate isn’t centred around Sweeney selling soaps infused with her bathwater or posting pictures of MAGA-inspired red caps. Instead, the Euphoria star is making rounds for her role in a contentious ad campaign with American Eagle Outfitters.

While the entire campaign sparked debate online, one particular ad has drawn especially intense criticism.

In it, Sweeney lounges artfully on a chaise while fastening a pair of American Eagle jeans. In a breathy voiceover, she says, “Genes are passed down from parents to offspring, often determining traits like hair colour, personality and even eye colour.”

As the camera slowly pans upward and she turns her eyes toward the viewer, Sweeney concludes, “My jeans are blue.”

Commentators and social media users have argued the campaign serves as a conservative dog whistle, conveying thinly veiled support for white supremacy and eugenics.

Sydney Sweeney in the most controversial American Eagle ad.

American Eagle released a statement defending the ad on August 1, writing “‘Sydney Sweeney Has Great Jeans’ is and always was about the jeans,” on Instagram.

Innocent marketing or intentional dog whistle?

Eugenics is a discredited ideology rooted in white supremacy and scientific racism. It promotes the false belief that racial groupings are biologically determined, and that some groups are genetically superior to others and should selectively reproduce to preserve their “good genes.”

Historically, the end goal of eugenics has been to eliminate so-called “bad genes” — often associated with non-white, disabled, poor or otherwise marginalized communities — so social elites can maintain their dominance.

Fashion advertising playing on eugenic themes has a long history. Commentators have gestured to similarities between the Sweeney ad and the infamous 1980s campaign for Calvin Klein featuring a then-15-year-old Brooke Shields, who rolls around in her Calvins while talking about genetic codes, evolution and survival of the fittest — language evocative of eugenic thinking.

The American Eagle campaign appears to be a direct homage to the Calvin campaign, but is rhetoric reminiscent of eugenics really something we want to reference in marketing?

The return of ‘traditional’ femininity

The American Eagle campaign is pointedly titled “Sydney Sweeney Has Great Jeans,” with “jeans” sometimes swapped out for “genes.” It’s clearly meant to be tongue-in-cheek.

But this is not just a harmless ad. If the campaign didn’t reflect broader cultural tensions, neither U.S. President Donald Trump nor Sen. Ted Cruz would have commented on it.

“The crazy Left has come out against beautiful women,” Cruz wrote in a tweet about the controversy. A right-wing media outlet went further, claiming body positivity was bringing “the giggling blonde with an amazing rack … to the brink of extinction.”

With its celebration of Sweeney’s conventionally attractive appearance, American Eagle has reintroduced the “traditional” feminine figure loudly and proudly. In this sense, the campaign symbolizes a changing of the cultural tides: out with body positivity, in with the “amazing rack” and all it signifies.

In our present cultural moment saturated with conservative messaging, Sweeney — a young, thin, white and sexualized Hollywood star — is hardly a surprising figure to hear extolling the quality of her “genes” (sorry, jeans).

From the rise of tradwife influencers and SkinnyTokers to the ritualized feminine performance of “morning shedders,” the campaign lands squarely within a broader revival of regressive feminine ideals wrapped in aspirational, white-washed beauty.

Exorcising self-love from the corporate agenda

As a feminist media scholar interested in the intersection of pop culture and the far right, my ongoing research explores the rise of anti-feminism and right-wing politics. We are no longer in the age of popular feminism, when corporations eagerly appropriated feminist rhetoric to sell their products and services.

In its place, brands are reverting to traditional imagery: thin, white women styled for the male gaze — a term referring to the objectification and sexualization of women in popular media, from film and television to fashion ads. It’s a strategy that has long worked for them, and it’s one they’re glad is back in vogue.

The aesthetic regression encapsulated in the Sweeney American Eagle campaign reveals what many critics suspected all along: the corporate embrace of feminism was never sincere.

Campaigns touting “love your body,” “empowerment,” and “confidence” in the late 2010s and early 2020s were intentionally designed to court progressive consumers and profit from the popularity of feminism. The core business model of these corporations — sell insecurities and reap profits for shareholders — had not fundamentally changed.

If anything, as other scholars argue, self-love marketing encouraged women to not only upgrade their bodies but also their minds. It was no longer culturally acceptable that women look good; they had to also feel good about their bodies. That standard required more work and, of course, products, which brands happily supplied.

Spurred on by an increasingly conservative political climate, many brands are no longer shy about expressing their motives. Thin is back in and whiteness is re-associated with rightness.

Living through the cultural backlash

As I have argued elsewhere, we are currently living in backlash times. In her 1991 book, journalist Susan Faludi wrote that backlash is “a recurring phenomenon” that “returns every time women begin to make some headway toward equality.”

Although many news articles are describing a consumer “backlash” to the Sweeney American Eagle campaign, I’m referring to something different: the rise of a cultural backlash against progressive social movements and politics. This backlash is currently taking shape across political, legal and economic domains, and it goes beyond a single ad.

Today’s current backlash is a reaction to popular feminism, Black Lives Matter, DEI and incisive systemic analyses found in feminist, anti-racist and queer scholarship and activism. The Sweeney campaign is just one expression of this larger pattern.

Faludi shrewdly observed that “images of the restrained women line the walls of the popular culture’s gallery” during periods of backlash. That insight feels newly relevant.

Just days after American Eagle dropped its campaign, Kim Kardashian’s company SKIMS released their “sculpt face wraps” — a product designed to give users a more “sculpted” jawline. On the SKIMS website, product images show women ensnared in products that resemble Hannibal Lecter’s famous mask or a surgical brace. They are disconcerting, to say the least.

If Faludi has taught us anything, it’s that a trend of images showing women restrained — physically or to rigidly defined roles — are not only harbingers of a menacing future, but are indicative of a chilling present that we must recognize to resist.

Meaghan Furlano does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Why Sydney Sweeney’s American Eagle campaign is part of a wider cultural backlash – https://theconversation.com/why-sydney-sweeneys-american-eagle-campaign-is-part-of-a-wider-cultural-backlash-262417

August 6, 2025

Wildfire season is starting weeks earlier in California – a new study shows how climate change is driving the expansion

Source: The Conversation – USA (2) – By Gavin D. Madakumbura, Postdoctoral Researcher, University of California, Los Angeles

Firefighters battle in Pacific Palisades, Calif., on Jan. 7, 2025 David Swanson/AFP via Getty Images

Fire season is expanding in California, with an earlier start to wildfire activity in most of the state. In parts of the northern mountains, the season is now starting more than 10 weeks earlier than it did in the 1990s, a new study shows.

Atmospheric scientists Gavin Madakumbura and Alex Hall, two authors of the study, explain how climate warming has been driving this trend and why the trend is likely to continue.

What did your study find about how wildfire season is changing?

Over the past three decades, California has seen a trend toward more destructive wildfire seasons, with more land burned, but also an earlier start to fire season. We wanted to find out how much of a role climate change was playing in that shift to an earlier start.

We looked at hundreds of thousands of fire records from 1992 to 2020 and documented when fire season started in each region of the state as temperatures rose and vegetation dried out.

While other research has observed changes in the timing of fire season in the western U.S., we identified the drivers of this trend and quantified their effects.

The typical onset of summer fire season, which is in May or June in many regions, has shifted earlier by at least one month in most of the state since the 1990s, and by about 2½ months in some regions, including the northern mountains. Of that, we found that human-caused climate change was responsible for advancing the season between six and 46 days earlier across most of the state from 1992 to 2020.

Our results suggest that as climate warming trends continue, this pattern will likely persist, with earlier starts to fire season in the coming years. This means longer fire seasons, increasing the potential for more of the state to burn.

California typically leads the nation in the number of wildfires, as well as the cost of wildfire damage. But the results also provide some insight into the risks ahead for other fire-prone parts of North America.

What’s driving the earlier start to fire season?

There are a few big contributors to long-term changes in wildfire activity. One is how much fuel is available to burn, such as grasses and trees. Another is the increase in ignition sources, including power lines, as more people move into wildland areas. A third is how dry the fuel is, or fuel aridity.

We found that fuel aridity, which is controlled by climate conditions, had the strongest influence on year-to-year shifts in the timing of the onset of fire season. The amount of potential fuel and increase in ignition sources, while contributing to fires overall, didn’t drive the trend in earlier fires.

Year-to-year, there will always be some natural fluctuations. Some years are wet, others dry. Some years are hotter than others. In our study, we separated the natural climate variations from changes driven by human-caused climate warming.

We found that increased temperatures and vapor pressure deficit – a measure of how dry the air is – are the primary ways climate warming is shifting the timing of the onset of fire season.

Just as a warmer, drier year can lead to an earlier fire season in a single year, gradual warming and drying caused by climate change are systematically advancing the start of fire seasons. This is happening because it is increasing fuel flammability.

Why has the start to fire season shifted more in some regions than others?

The biggest shifts we’ve seen in fire season timing in California have been in the northern mountains.

In the mountains, the winter snowpack typically keeps the ground and forests wet into summer, making it harder for fires to burn. But in warmer years, when the snowpack melts earlier, the fire potential rises earlier too.

A map of California shows where fires season is starting earlier. Most of the state is starting at least 1 days per year earlier now. — Gavin Madakumbura, et al., Science Advances, 2025

Those warmer years are becoming more common. The reason climate change has a stronger impact in mountain regions is that snowpack is highly sensitive to warming. And when it melts sooner, vegetation dries out sooner.

In contrast, drier regions, such as desert ecoregions, are more sensitive to precipitation changes than to temperature changes. When assessing the influence of climate change in these areas, we mainly look at whether precipitation patterns have shifted due to climate warming. However, there is a lot of natural year-to-year variability in precipitation, and that makes it harder to identify the influence of climate change.

It’s possible that when precipitation changes driven by climate warming become strong enough, we may detect a stronger effect in these regions as well.

Gavin D. Madakumbura receives funding from the Gordon and Betty Moore Foundation.

Alex Hall receives funding from the NSF, DOE, NOAA, LADWP, and State of California, among other sources.

– ref. Wildfire season is starting weeks earlier in California – a new study shows how climate change is driving the expansion – https://theconversation.com/wildfire-season-is-starting-weeks-earlier-in-california-a-new-study-shows-how-climate-change-is-driving-the-expansion-262666

August 6, 2025

How to talk to your friends about climate action

Source: The Conversation – UK – By Bella Zanin, Knowledge Exchange Associate, Centre for Climate Change and Social Transformations, University of Bath

How often do you chat about climate change? When the weather’s been “a bit crazy”? Maybe with an estranged uncle over Christmas dinner? Recent polling reveals that over half of British adults rarely or never share their opinions about our warming planet.

Why does this matter? Because talking about climate change is one of the most important things we can do to tackle it. Conversations shape social norms, and social norms shape behaviour.

To be clear: it’s not about convincing your friends, family, neighbours or colleagues to care about climate change. Chances are they already do. It’s about letting them know you care too – that it’s normal to care, and typical to take action.

Talking about climate change is how we break the taboo, build a sense of unity, inspire hope and kickstart action. And it’s easier than you might think.

The analysis by insights platform Climate Barometer finds that 56% of Brits say they “rarely” or “never” share their opinions about climate change in day-to-day life. Its survey of 2,796 British adults, conducted in April 2025, revealed that only one in ten regularly express their climate views. This “climate silence” persists even among supporters of environmental policies.

Other studies paint a slightly chattier picture. In Ireland, 33% of people reportedly discuss climate change with family and friends “often”, while 39% of respondents to the Scottish Climate Survey had spoken about climate change at least weekly in the last month.

A similar pattern emerges in sport. Research by my colleagues at the Centre for Climate Change and Social Transformations found one-third of UK football fans speak to their friends, family and colleagues “often” or “very often” about climate change – although they are much less likely to speak to other football fans and strangers about the topic.

While climate chatter varies with things like age, social grade, education and political affiliation, generally people aren’t talking about climate change very often, especially when it involves sharing their opinion.

Yet numerous surveys show that most people are worried about rising global temperatures, willing to make sustainable lifestyle swaps, and support ambitious government climate policy. The problem is, many of us don’t know that others are feeling and behaving this way.

two women chatting outside in park — People care more about climate change than some might think.
Bricolage/Shutterstock

Polling demonstrates that 89% of people globally want stronger political action on climate issues, with eight in ten being in favour of taxing oil and gas corporations to pay for climate damages. In Britain, the public support most net zero policies, despite media reports of a shattered consensus, and want more of their energy produced by renewables.

They are acting, too. Recently, over 5,000 people travelled to Westminster for one of the decade’s largest climate lobbies. And earlier this summer, over 110,000 UK residents urged the government to ban fossil fuel advertising. Heat pump installations, electric car sales and consumption of meat-free meals are all on the rise too.

However, if we don’t talk to each other about climate issues – and climate lobbies don’t make front-page news – it’s easy to mistakenly assume that others aren’t willing to act on climate change.

This cognitive error – repeatedly making incorrect assumptions about other people’s beliefs and behaviour – is called “pluralistic ignorance”. This phenomenon, also known as “perception gaps”, is something that politicians unfortunately fall victim to as well, because they consistently underestimate public support for net zero policies.

Social influence is incredibly powerful. If you’ve ever laughed at a joke that everyone else was laughing at even though you didn’t understand it, you’ll know this to be true. People don’t like deviating from social norms. So, if we think the norm is not to care about climate change, we won’t take collective climate action.

Talking is the antidote to this “spiral of silence” – it makes climate action socially acceptable, sparking change beyond our own lives. Indeed, just knowing someone with a heat pump makes people more likely to consider installing one. So, chatting can be an effective form of climate action.

How to talk about climate change

You might be hesitant to chat about climate change. But luckily, research shows you don’t need to be an expert or get political to have effective climate conversations.

In fact, you could be the best climate messenger for the people in your life. We tend to trust information from our friends and family, and more readily accept advice from those with common interests – as researchers investigating how to encourage meat-eaters to reduce their meat intake discovered.

There’s little to be gained from discussing climate change with climate deniers, because people with strong views tend to dismiss information that challenges their beliefs. Instead, talk to the majority of people who are worried about climate change, but don’t know what to do about it.

Chatting to your mates is a good place to start: you probably already have a trusting relationship and shared interests. You could also approach your MP or local councillor to call for stronger policy action – our academic review and interviews with MPs show that voters’ views influence politicians’ engagement with climate change.

If you’re wondering how to begin a climate conversation, start by finding some common ground. Find a value or interest that you and your conversation partner share and explore how it relates to climate change. It can be as simple as asking a foodie friend: “I’m really enjoying cooking more veggie meals – have you got any good recipes?”

Climate framings that tend to unite rather than divide include improving health, benefiting the local community, protecting future generations, achieving balance with nature and avoiding waste. Your experience of climate impacts (hot days, storms, flooding) can also be a good bridging topic – Brits love talking about the weather.

Chatting about climate change is one of the most powerful (and overlooked) climate solutions. It normalises caring, boosts hope and catalyses action. You’re an expert on your own experience of climate impacts and solutions. So why not share it? Ask a question. Start a conversation. You never know who you might inspire.

Don’t have time to read about climate change as much as you’d like?

Get a weekly roundup in your inbox instead. Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. Join the 45,000+ readers who’ve subscribed so far.

Bella Zanin receives funding from The Economic & Social Research Council.

– ref. How to talk to your friends about climate action – https://theconversation.com/how-to-talk-to-your-friends-about-climate-action-261023

August 6, 2025

Russia’s decision to pull out of nuclear treaty makes the world more dangerous

Source: The Conversation – UK – By Matthew Powell, Teaching Fellow in Strategic and Air Power Studies, University of Portsmouth

Russia has announced it will no longer uphold its obligations under the intermediate-range nuclear forces (INF) treaty, signed by the Soviet Union and the United States in December 1987. The decision has raises questions about the future of nuclear deterrence and the danger of global nuclear proliferation.

The timing of this announcement from the Kremlin must be considered. It was just days after a spat on social media between the US president, Donald Trump, and former Russian president Dymitri Medvedev, a strong ally of Vladimir Putin.

Responding to the US president’s threats to punish Russia for its war in Ukraine, Medvedev took to X on July 28 to warn Trump that: “Each new ultimatum is a threat and a step towards war. Not between Russia and Ukraine, but with his own country.” Medvedev added: “Don’t go down the Sleepy Joe road!”

Trump responded by announcing that the US would redeploy two of its nuclear submarines into closer striking distance with Russia.

Russia’s decision also comes just three days before the deadline of August 8 set by Trump for Russia to agree to a ceasefire in its war with Ukraine.

It’s also important to remember that, while the Russian withdrawal from the INF treaty is attracting attention now, the US withdrew from the same treaty in August 2019, during Trump’s first presidency. So it’s tempting to see all this as diplomatic posturing.

However, when it comes to nuclear weapons – and given the rising global tensions – such moves must be taken seriously.

Arms limitation treaties

The INF treaty was part of a series of agreements between the US and Soviet Union that began with the Strategic Arms Limitation Talks (Salt) of 1972 and 1979. These led to agreements to reduce the strategic weapons held by both sides, including intercontinental ballistic missiles, submarine-launched ballistic missiles and ballistic missile defences.

This was then followed in 1987 by the INF treaty, which was struck between Ronald Reagan and Mikhail Gorbachev. Both sides agreed to reduce their stockpile of ground-based ballistic and cruise missiles with a range of between 500km to 5,500km (an entire category of nuclear weapon).

They also put in place provisions for inspection to ensure both were keeping to the agreement. Thanks to the treaty, 2,692 missiles were eliminated.

Despite these agreements, there remain significant stockpiles of nuclear weapons, with Russia and the US the most heavily armed nuclear powers. The size of their stockpiles is difficult to assess with complete accuracy, but the latest estimate by the non-profit Arms Control Association is that Russia is the most heavily armed nuclear power with 5,580 warheads, while the US maintains 5,225.

Both powers operate what is known as the “nuclear triad” of air, land and sea-launched systems. Russia’s decision to withdraw from the INF treaty only concerns ground-based missile systems, which in 1987 had the capability of striking targets in Europe withing a short period of time. Air- or sea-launched nuclear weapons were not seen at the time as a major concern to European security so were not covered by the treaty.

The other remaining non-proliferation treaty, New Start, which limits the US and Russia’s total number of deployed strategic missiles, warheads and launchers, does cover air and sea-launched weapons. However, its future is also in doubt.

Russia claims to still abide by the central limits of the agreement, despite having suspended official participation in February 2023. But the deal is due to expire in February 2026 and there are real concerns whether it will be possible for new negotiations to take place given the Russo-Ukrainian War and the current state of relations between Washington and Moscow.

There is also currently no treaty that covers the amount of tactical nuclear weapons a nation can hold. These are designed to be used on the battlefield (rather than against long-range targets) and, as they have never been deployed, it is not clear what damage they could do to a nation’s own forces as well as the enemy. This raises interesting questions with regards to the proximity of Nato members to Ukraine and Russia.

Defence systems

In May 2025, Trump announced a funding package of US$175 billion (£131 billion) for the development of a new “Golden Dome” defensive system that he said would render Russian strategic nuclear weapons redundant. Critics have pointed out that the US attempted something similar before without success, the Reagan-era “Star Wars” defence system, which ended up being scrapped as too expensive.

Missile defence systems against nuclear weapons do exist, such as the US ground-based midcourse defense system, which aims to track and shoot down incoming nuclear missiles. But these have never actually been tested in operational conditions. So the extent to which they provide guaranteed protection against every nuclear warhead is not known.

Russia’s decision to end compliance with the INF treaty should be viewed by the west with a great deal of concern. But it should also be seen in the context of previous Russian statements about its nuclear arsenal and willingness to use it, as well as the recent changes to the country’s nuclear doctrine to make it easier for Russia to use these weapons.

The Kremlin has made several changes to this doctrine since it started the war in Ukraine, usually to warn Kyiv’s western allies of the potential consequences of supplying more powerful and advanced weapons for use against Russia.

The true power of nuclear weapons in the 21st century is not necessarily their awesome destructive capacity, but the way that awesome destructive capacity can be used by nuclear-armed states to manoeuvre and protect their political power.

Matthew Powell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Russia’s decision to pull out of nuclear treaty makes the world more dangerous – https://theconversation.com/russias-decision-to-pull-out-of-nuclear-treaty-makes-the-world-more-dangerous-262742

August 6, 2025

We fed people a milkshake with 130g of fat to see what it did to their brains – here’s what we learned

Source: The Conversation – UK – By Chris Marley, Senior Lecturer in Exercise Physiology, University of South Wales

An enormous milkshake BrittanyD/Shutterstock

A greasy takeaway may seem like an innocent Friday night indulgence. But our recent research suggests even a single high-fat meal could impair blood flow to the brain, potentially increasing the risk of stroke and dementia.

Dietary fat is an important part of our diet. It provides us with a concentrated source of energy, transports vitamins and when stored in the body, protects our organs and helps keep us warm. The two main types of fat that we consume are saturated and unsaturated (monounsaturated and polyunsaturated), which are differentiated by their chemical composition.

But these fats have different effects on our body. For example, it is well established that eating a meal that is high in saturated fat, such as that self-indulgent Friday night takeaway pizza, can be bad for our blood vessels and heart health. And these effects are not simply confined to the heart.

The brain has limited energy stores, which means it is heavily reliant on a continuous supply of blood delivering oxygen and glucose to maintain normal function.

One of the ways the body maintains this supply is through a process known as “dynamic cerebral autoregulation”. This process ensures that blood flow to the brain remains stable despite everyday changes in blood pressure, such as standing up and exercising. It’s like having shock absorbers that help keep our brains cool under pressure.

But when this process is impaired, those swings in blood pressure become harder to manage. That can mean brief episodes of too little or too much blood reaching the brain. Over time, this increases the risk of developing conditions like stroke and dementia.

What role might diet play?

After eating a meal high in saturated fat, levels of fat in the blood rise and peak after around four hours. At the same time, blood vessels become stiffer and lose their ability to relax and expand. This restricts blood flow around the body. But little is known about what happens to the brain during this time and how well its blood supply is protected.

To address this for the first time, we recruited 20 young men between the ages of 18 and 35, and 21 men between 60 and 80. We measured how well blood vessels linked to heart and brain health worked before, and four hours following, consumption of a meal high in saturated fat.

We assessed how well a blood vessel in the arm could open up in response to increased blood flow to obtain an indication of heart health. This is a method known as “flow-mediated dilatation”.

To evaluate how well blood vessels in the brain could cope with swings in blood pressure, our participants performed body-weight squats. We used ultrasound to determine how well blood flowed through vessels during both methods.

The test meal was a milkshake, which we called “the brain bomb” because it consisted mostly of heavy whipping cream. The drink contained 1,362 calories and 130g of fat, mimicking the fat load of a fast-food takeaway.

Our findings confirmed previous research that has shown that a high-fat meal impairs the ability of the blood vessels linked to heart health to open in both young and old participants. These impairments reduced the brain’s ability to buffer changes in blood pressure. This was more pronounced (by about 10%) in the older adults, suggesting that older brains may be more vulnerable to the effects of the meal.

Although we didn’t directly test for the long-term effects of a high-fat meal on mental functioning in this study, we have previously shown that such a meal increases free radicals (unstable, cell-damaging molecules) and decreases nitric oxide (molecules that help blood vessels relax and open up to transport oxygen and glucose around the body).

This may explain the reduced blood flow regulation we observed in our recent study.

This has important clinical implications. While an occasional takeaway is unlikely to cause harm on its own, our results suggest that even one fatty meal has an immediate effect on the body.

Our study highlights the importance of consuming a diet that is low in saturated fat to protect not only our heart health, but also our brain health. This is particularly important for older adults whose brains appear to be more vulnerable to the effects of such a meal and are already at increased risk of stroke and neurodegenerative diseases.

The NHS recommendeds that men consume no more than 30g of saturated fat a day, while women should consume no more than 20g. Yet many of us routinely exceed that, particularly during weekend takeaways, pub lunches or fast-food splurges.

What’s more, we may spend much of our waking lives in a post-meal state. This period, known as “post-prandial lipaemia”, is when fat levels are elevated, and when the body, it seems, may be most at risk.

Food for thought

There’s still so much more we need to learn about this topic.

Public health guidance recommends swapping saturated fats for polyunsaturated ones. These are found in foods like oily fish, walnuts and seeds, which are associated with better heart and brain health over the long term. But we don’t yet know how the brain responds to a single meal that is high in polyunsaturated fat.

Nor do we know how the female brain responds to a high-fat meal. This is a crucial gap in our knowledge since women face a greater risk of stroke and dementia in later life compared to men.

Our study offers a timely reminder that diet doesn’t just shape our long-term health. It also affects our body and brain in real time. And as we’re learning, when it comes to protecting brain health, every meal may count.

D.M.B. is supported by a Royal Society Wolfson Research Fellowship (Grant No. WM170007). D.M.B. is Editor-in-Chief of Experimental Physiology, Chair of the Life Sciences Working Group, member of the Human Spaceflight and Exploration Science Advisory Committee to the European Space Agency, member of the Space Exploration Advisory Committee to the UK and Swedish National Space Agencies and member of the National Cardiovascular Network for Wales and South-East Wales Vascular Network. D.M.B. is also affiliated to Bexorg, Inc. (USA) focused on the technological development of novel biomarkers of cerebral bioenergetic function and structural damage in humans.

Chris Marley does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. We fed people a milkshake with 130g of fat to see what it did to their brains – here’s what we learned – https://theconversation.com/we-fed-people-a-milkshake-with-130g-of-fat-to-see-what-it-did-to-their-brains-heres-what-we-learned-259961