Category: The Conversation

Source: The Conversation – Global Perspectives – By Ray Laurence, Professor of Ancient History, Macquarie University

Roman concrete is pretty amazing stuff. It’s among the main reasons we know so much about Roman architecture today. So many structures built by the Romans still survive, in some form, thanks to their ingenious concrete and construction techniques.

However, there’s a lot we still don’t understand about exactly how the Romans made such strong concrete or built all those impressive buildings, houses, public baths, bridges and roads.

Scholars have long yearned for more physical evidence from Roman worksites to provide clues.

Now, a new study – led by researchers from the Massachusetts Institute of Technology (MIT) and published in the journal Nature Communications – sheds new light on Roman concrete and construction techniques.

That’s thanks to details sifted from partially constructed rooms in Pompeii – a worksite abandoned by workers as Mount Vesuvius erupted in 79 CE.

New clues about concrete making

The discovery of this particular building site hit the news early last year.

The builders were quite literally repairing a house in the middle of the city, when Mount Vesuvius blew up in the first century CE.

This unique find included tiles sorted for recycling and wine containers known as amphorae that had been re-used for transporting building materials.

Most importantly, though, it also included evidence of dry material being prepared ahead of mixing to produce concrete.

It is this dry material that is the focus of the new study. Having access to the actual materials ahead of mixing represents a unique opportunity to understand the process of concrete making and how these materials reacted when water was added.

This has re-written our understanding of Roman concrete manufacture.

Self-healing concrete

The researchers behind this new paper studied the chemical composition of materials found at the site and defined some key elements: incredibly tiny pieces of quicklime that change our understanding of how the concrete was made.

Quicklime is calcium oxide, which is created by heating high-purity limestone (calcium carbonate).

The process of mixing concrete, the authors of this study explain, took place in the atrium of this house. The workers mixed dry lime (ground up lime) with pozzolana (a volcanic ash).

When water was added, the chemical reaction produced heat. In other words, it was an exothermic reaction. This is known as “hot-mixing” and results in a very different type of concrete than what you get from a hardware store.

Adding water to the quicklime forms something called slaked lime, along with generating heat. Within the slaked lime, the researchers identified tiny undissolved “lime clasts” that retained the reactive properties of quicklime. If this concrete forms cracks, the lime clasts react with water to heal the crack.

In other words, this form of Roman concrete can quite literally heal itself.

Techniques old and new

However, it is hard to tell how widespread this method was in ancient Rome.

Much of our understanding of Roman concrete is based on the writings of the ancient Roman architect Vitruvius.

He had advised to use pozzolana mixed with lime, but it had been assumed that this text did not refer to hot-mixing.

Yet, if we look at another Roman author, Pliny the Elder, we find a clear account of the reaction of quicklime with water that is the basis for the exothermic reaction involved in hot-mixing concrete.

So the ancients had knowledge of hot-mixing but we know less about how widespread the technique was.

Maybe more important is the detail in the texts of experimentation with different blends of sand, pozzolana and lime, leading to the mix used by the builders in Pompeii.

The MIT research team had previously found lime clasts (those tiny little bits of quicklime) in Roman remains at Privernum, about 43 kilometres north of Pompeii.

It’s also worth noting the healing of cracks has been observed in the concrete of the tomb of noblewoman Caecilia Metella outside Rome on the Via Appia (a famous Roman road).

Now this new Pompeii study has established hot-mixing happened and how it helped improve Roman concrete, scholars can look for instances in which concrete cracks have been healed this way.

Questions remain

All in all, this new study is exciting – but we must resist the assumption all Roman construction was made to a high standard.

The ancient Romans could make exceptional concrete mortars but as Pliny the Elder notes, poor mortar was the cause of the collapse of buildings in Rome. So just because they could make good mortar, doesn’t mean they always did.

Questions, of course, remain.

Can we generalise from this new study’s single example from 79 CE Pompeii to interpret all forms of Roman concrete?

Does it show progression from Vitruvius, who wrote some time earlier?

Was the use of quicklime to make a stronger concrete in this 79 CE Pompeii house a reaction to the presence of earthquakes in the region and an expectation cracking would occur in the future?

To answer any of these questions, further research is needed to see how prevalent lime clasts are in Roman concrete more generally, and to identify where Roman concrete has healed itself.

Ray Laurence 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. A 2,000-year-old building site reveals the raw ingredients for ancient Roman self-healing concrete – https://theconversation.com/a-2-000-year-old-building-site-reveals-the-raw-ingredients-for-ancient-roman-self-healing-concrete-271405

Source: The Conversation – Global Perspectives – By Shawna Foo, Senior Research Fellow, School of Life and Environmental Sciences, University of Sydney

During the last global coral bleaching event in 2023 and 2024 , the Great Barrier Reef experienced the highest temperatures for centuries and widespread bleaching. With bleaching events becoming more frequent, the very existence of coral reefs is under threat.

This, in case it’s not clear, is a major problem. Coral reef ecosystems are essential for many species of plants and animals to survive. They provide humans with essential food security (many fish can’t survive without them), prosperity (via tourism and fisheries) and shoreline protection.

But heat stress can weaken corals, making them vulnerable to disease. At the same time, warm conditions can make the pathogens that cause disease stronger and more virulent.

For our research, published today in Proceedings of the Royal Society B, we tracked hundreds of coral colonies on One Tree Reef in the southern Great Barrier Reef in Australia during a 2024 heatwave. Weakened by heat stress, one particular type of boulder coral, Goniopora, developed a disease called black band disease.

These corals are old – probably at least 100 years old – and are like the old growth forest of the reef.

Six months later, 75% of these coral colonies in the reef community we monitored were dead.

This is especially worrying because these massive corals are normally quite resilient to heat stress. Even the strong are now struggling to survive.

And their huge, dead bodies can detach from the reef and hurtle around, crushing and destroying other corals in their path.

What we found on the Great Barrier Reef

We were originally tracking multiple sites on One Tree Reef in response to an extreme heatwave. We wanted to understand which coral species were more resistant and which were more sensitive to heat stress.

It was a surprise to see the bleached boulder corals quickly get infected by black band disease.

Black band disease is caused by a group of pathogenic microbes that kill coral tissue. These pathogens naturally occur in the environment but this is the first time such a disease epidemic has been observed on the Great Barrier Reef.

The disease appears as a black band, leaving behind bare skeleton as it destroys the coral tissue and spreads throughout the colony. Around the world, black band disease has been recorded on many different coral species. This disease has wiped out reefs in the Caribbean and fundamentally altered reef structure and function.

A review of coral diseases on the Great Barrier Reef shows that black band disease is mostly found on branching corals. Branching corals are more delicate and tree-like in comparison to sturdy, boulder corals.

Our findings are curious because on One Tree Reef only one particular species, a normally resilient boulder-like coral, was affected.

Black band disease virtually wiped out these corals at the site we were monitoring.

In other words, ordinarily strong and resilient corals are now succumbing to this disease. This is extremely troubling.

Why is this worrying?

This boulder-like coral, specifically from the genus Goniopora, has long, flower-like tentacles that sway with the currents.

A key reef-building coral on the Great Barrier Reef, it is very slow-growing compared to branching corals. Goniopora tends to be more resistant to disturbance and is often found in areas of lower water quality.

Living for hundreds of years, it can form extensively large coral patches supporting a wide range of organisms. These long-lived corals form the backbone structure of reefs providing refuge for a range of invertebrates and fish. Because of their size, they help buffer coastlines from waves.

We found that six months after the 2024 heatwave, the colonies we were tracking had been all but wiped out. At least 75% were dead.

Of the surviving colonies, 64% had experienced partial coral tissue death due to black band disease. While other species of corals showed signs of recovery after the heatwave, we didn’t see any recovery at all for the boulder corals.

Killer bowling balls

One Tree Reef is one of the most protected coral reefs on the Great Barrier Reef.

Previously, outbreaks of black band disease have been linked to coastal stressors such as pollution and high nutrients. Given One Tree Reef is 80 km offshore in open ocean, its isolation protects it from land-based pressures.

This makes the disease prevalence and rapid spread at One Tree Reef particularly concerning.

Once the coral tissue is killed by the disease, the skeleton is quickly covered by algae (and other organisms) that eat away at the skeleton. We noticed the breakdown of the boulder coral skeleton began surprisingly fast after the colony died.

This process usually takes many months to years. By six months, though, we found these boulder corals were unstable and began to detach from the reef.

This is dangerous as they can act like bowling balls if moved by waves and tropical cyclones, destroying surrounding reef.

These large structural corals that have survived for hundreds of years are now lost from this reef, resulting in a potentially permanent change to the ecosystem.

Black band disease is one of the earliest recorded coral diseases, first identified in the Caribbean. There, it has driven high mortality in corals and reshaped entire coral communities. Our results are beginning to echo these devastating disease outbreaks seen in the Caribbean.

With coral disease expected to rise with climate change, our findings reinforce the need for urgent global action and for ambitious climate and reduced emissions targets.

Shawna Foo receives funding from the Australian Research Council, Westpac Scholars Trust and the University of Sydney.

Maria Byrne receives funding from the Australian Research Council and the Reef Trust.

– ref. We watched these coral colonies succumb to black band disease. 6 months later, 75% were dead – https://theconversation.com/we-watched-these-coral-colonies-succumb-to-black-band-disease-6-months-later-75-were-dead-264895

Source: The Conversation – Global Perspectives – By Lisa M. Given, Professor of Information Sciences & Director, Social Change Enabling Impact Platform, RMIT University

After months of anticipation and debate, Australia’s social media ban is now in force.

Young Australians under 16 must now come to grips with the new reality of being unable to have an account on some social media platforms, including Instagram, TikTok and Facebook.

Only time will tell whether this bold, world-first experiment will succeed. Despite this, many countries are already considering following Australia’s lead.

But there are other jurisdictions that are taking a different approach to try and keep young people safe online.

Here’s what’s happening overseas.

A global movement

In November, the European parliament called for a similar social media ban for under 16s.

The President of the European Commission, Ursula von der Leyen, said she has been studying Australia’s restrictions and how they address what she described as “algorithms that prey on children’s vulnerabilities”, leaving parents feeling powerless against “the tsunami of big tech flooding their homes”.

In October, New Zealand announced it would introduce similar legislation to Australia’s, following the work of a parliamentary committee to examine how best to address harm on social media platforms. The committee’s report will be released in early 2026.

Pakistan and India are aiming to reduce children’s exposure to harmful content by introducing rules requiring parental consent and age verification for platform access, alongside content moderation expectations for tech companies.

Malaysia has announced it will ban children under 16 from social media starting in 2026. This follows the country requiring social media and messaging platforms with eight million or more users to obtain licenses to operate, and use age verification and content-safety measures from January 2025.

France is also considering a social media ban for children under 15 and a 10pm to 8am curfew for platform use for 15- to 18-year-olds. These are among 43 recommendations made by a French inquiry in September 2025, which also recommended banning smartphones in schools, and implementing a crime of “digital negligence for parents who fail to protect their children”.

While France introduced a requirement in 2023 that platforms obtain parental consent for children under 15 to create social media accounts, it has yet to be enforced. This is also the case in Germany. There, children aged between 13 and 16 can only access platforms with parental consent, but without formal checks in place.

And, in Spain, the minimum age for social media accounts will rise from 14 to 16, unless parents provide consent.

Norway announced plans in July to restrict access to social media for under 15s. The government explained the law would be “designed in accordance with children’s fundamental rights, including freedom of expression, access to information, and the right to association”.

In November, Denmark announced it would “ban access to social media for anyone under 15”. However, unlike Australia’s legislation, parents can override the rules to enable 13- and 14-year-olds to retain platform access. Yet there is no date for implementation, with lawmakers expected to take months to pass the legislation.

It’s also unclear how Denmark’s ban will be enforced. But the country does have a national digital ID program that may be used.

In July, Denmark was named as part of a pilot program (with Greece, France, Spain, and Italy) to trial an age verification app that could be launched across the European Union for use by adult content sites and other digital providers.

Some pushback

The implementation of similar restrictions is not being taken up everywhere.

For example, South Korea has decided against a social media ban for children. But it will ban the use of mobile phones and other devices in classrooms starting in March 2026.

In the city of Toyoake (south-west of Tokyo, Japan), a very different solution has been proposed. The city’s mayor, Masafumi Koki, issued an ordinance in October, limiting the use of smartphones, tablets, and computers to two hours per day for people of all ages.

Koki is aware of Australia’s social media restrictions. But as he explained:

If adults are not held to the same standards, children will not accept the rules.

While the ordinance has faced backlash, and is non-binding, it prompted 40% of residents to reflect on their behaviour, with 10% reducing their time on smartphones.

In the United States, the opposition to Australia’s social media restrictions has been extremely vocal and significant.

American media and technology companies have urged President Donald Trump to “reprimand” Australia over its legislation. They argue American companies are being unfairly targeted and have lodged formal complaints with the Office of US Trade.

President Trump has stated he would stand up to any countries that “attacked” American technology companies. The US recently called eSafety Commissioner Julie Inman-Grant to testify in front of Congress. US Republican Jim Jordan claimed her enforcement of Australia’s Online Safety Act “imposes obligations on American companies and threatens speech of American citizens”, which Inman-Grant strongly denied.

The world will keep watching

While much of the world seems united in concern about the harmful content and algorithmic features children experience on social media, only one thing is clear – there is no silver bullet for addressing these harms.

There is no agreed set of restrictions, or specific age at which legislators agree children should have unrestricted access to these platforms.

Many countries outside Australia are empowering parents to provide access, if they believe it is right for their children. And many countries are considering how best to enforce restrictions, if they implement similar rules.

As experts point to the technical challenges in enforcing Australia’s restrictions, and as young Australians consider workarounds to maintain their accounts or find new platforms to use, other countries will continue to watch and plan their next moves.

Lisa M. Given receives funding from the Australian Research Council and Australia’s eSafety Commission. She is a Fellow of the Academy of the Social Sciences in Australia and the Association for Information Science and Technology.

– ref. Australia’s social media ban is now in force. Other countries are closely watching what happens – https://theconversation.com/australias-social-media-ban-is-now-in-force-other-countries-are-closely-watching-what-happens-271407

Source: The Conversation – Global Perspectives – By Vivian Gerrand, Associate Lecturer, Australian National University; Deakin University

The manosphere is big business today. Once a niche network lurking on the margins of the internet, this diverse community of male supremacist cultures has grown into a transnational profit-making enterprise.

Our new review of the growing body of research on the manosphere reveals how it’s evolved.

It used to be largely special interest men’s rights groups, such as pick-up artists and incels (involuntary celibates). It’s now a widely mainstreamed and commercialised ecosystem, led by high-profile influencers or “manfluencers”.

Here’s how the manosphere has found ways to cash in on the insecurities of men and boys, expand its reach, and how doing so has ensured the movement’s longevity online.

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The manosphere is a dark, but growing part of the internet that’s harming everyone who gets sucked into it. In this three-part series, Mapping the Manosphere, we’ve asked leading global experts how it works, what the dangers are and how this online phenomenon is playing out in real life.

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Grifting their way to glory

Manosphere grift often takes the form of financial, health and relationship advice.

Platforms, driven by recommending similar content to consumers to keep them online longer, then push this content further.

Charged by anti-feminism, social media algorithms push apparent solutions for younger male internet users’ insecurities. This monetises them without providing true support.

The “thought leaders” of the manosphere maintain and grow their audiences by tapping into boys’ concerns about looks, economic futures and ability to attract women.

The solution they present is two-fold: urge viewers to direct their anger and resentment toward women and feminism, and buy the manfluencer’s products.

For example, many manfluencers have their own subscription-based “academies”, which they promote as an alternative to school or college. These can cost thousands of dollars.

Followers can buy one-on-one dating advice or access to networking groups of like-minded men.

There’s also manosphere podcast merchandise, including books.

Some sell supplements, like turmeric capsules, or swear by testosterone injections. Others peddle wellness-adjacent tech, such as water filters.

Many men and boys buying into this content have been raised on neoliberal ideas of winners and losers, hustle culture and individual choice.

In the manosphere, there’s no space for the collective, or discussions of systems and structures that negatively affect most of us. In this worldview, your perceived failings are all your own fault.

And so, manfluencers promise solutions to the isolation, alienation and precarity of existence under capitalism by offering up more of the same.

The rise of the manfluencer

In addition to its overtly anti-women messaging, today’s manosphere often operates through subtler forms of sexism.

Many creators promote gender essentialism: the idea that men and women are born with significant cognitive and personality differences, determined biologically rather than culturally.

This shift towards “alpha” masculinity marks a significant shift in men’s rights politics. It’s helped the movement have more mainstream appeal beyond the smaller corners of the web it used to occupy.

Male supremacists can now use influencer culture to gain substantial personal wealth, while promoting right-wing reactionary politics.

For example, Black manfluencers Myron Gaines and Walter Weekes regularly feature white supremacist guests and debates on their podcast, Fresh and Fit.

At the same time, mainstream platforms such as TikTok and YouTube Shorts have been instrumental for increasing commercialisation.

Experimental studies using sockpuppet accounts have looked at how quickly and how often young male users are being served manosphere content.

In the study conducted by Dublin City University, all of the accounts, whether they sought out the manosphere or not, were fed toxic content within the first 23 minutes of the experiment. Manosphere content appeared within the first 26 minutes.

New ways to monetise grievance

As the manosphere has expanded and shifted, it has also diversified. More users can find self-help advice from people who look like them.

There’s greater visibility of ethnic diversity and non-white actors in the male supremacist ecosystem.

Gaines and Weekes use language to appeal to Black men. They selectively invoke the discourse of social justice while maintaining a misogynist, frequently homophobic and transphobic outlook.

Other manfluencers, such as Andrew Tate and Sneako, say they’ve converted to Islam. This has also broadened the manosphere’s appeal.

It’s clear the movement can shape-shift to reach ever-changing moods and markets. By being agile and adaptable, the manosphere is entrenching itself in the online landscape.

The female equivalent

There’s also a growing presence of anti-feminist “trad” women accounts.

While previously associated exclusively with white women, Black women creators have become big tradwives and “pick-me” girls (a derogatory term for anti-feminist women). They tailor their content strategically for Black manosphere men.

These successful women digital entrepreneurs encourage their followers to reject hustle culture and instead embrace traditional marriage through service to their husbands.

As with most manosphere trends we observed in our review, the phenomenon of pick-mes and tradwives is heavily influenced by socioeconomic conditions. Women in these situations reject the “strong Black woman” stereotype of economic struggle in favour of finding dignity in marriage and homemaking.

In a patriarchal bargain, husbands become “bosses” for these women, to whom they willingly submit.

Ideology meets industry

To fully confront the socioeconomic forces shaping digital gender politics, it’s essential to consider the manosphere as both ideology and industry.

Manfluencers, self-styled gurus and ideological entrepreneurs operate within a digital attention economy that converts human insecurity into capital.

As the manosphere becomes more diverse and ideologically unstable (driven predominantly by the whims of algorithmic capitalism), there is an increasingly urgent need to educate boys and men. They need to know more about gendered disinformation, mental health, gender-based abuse and the mechanics of social media and influencer culture.

By better understanding this monetisation of grievance and equipping boys to respond critically to it, we can build healthier and more gender-equitable online cultures.

Vivian Gerrand receives funding from the Australian Research Council.

Josh Roose receives funding from The Australian Research Council and Department of Home Affairs.

Michael Flood receives funding from the Australian Research Council.

Debbie Ging 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. Hustle, muscle and grift: how the manosphere has grown into a money-making machine – https://theconversation.com/hustle-muscle-and-grift-how-the-manosphere-has-grown-into-a-money-making-machine-262432