Latest news with #LondonSchoolofHygiene&TropicalMedicine
The Independent
16-04-2025
- Health
- The Independent
Nitrogen-fertilised grassland more likely to trigger hay fever, study suggests
Grasslands that have been cultivated using nitrogen fertilisers may be more likely to trigger hay fever, a study suggests. The paper, published in The Lancet Planetary Health journal, found that these grasslands could produce six times more pollen than their unfertilised counterparts. As spring arrives in the UK, many Britons are experiencing the flare-up of hay fever symptoms, while over the decades the rate of pollen allergies has increased globally. Scientists believe that one reason for this rise could be due to atmospheric nitrogen pollutants affecting pollen and leading to an increased release of allergens. However, there has been little research into the impact that nitrogen fertilisers, which are a major source of environmental pollution, has on pollen. In the new Lancet paper, the authors said: 'Pollen allergy, encompassing allergic rhinitis, conjunctivitis, and asthma, is a growing public health concern worldwide. 'It causes a reduced quality of life in patients and has a substantial economic burden due to healthcare costs and lost patient productivity.' The researchers claimed their study is the first to suggest a clear relationship between nitrogen fertiliser and pollen count and its ability to trigger allergies. The authors compared pollen samples from 25 nitrogen-fertilised and 25 non-fertilised grasslands in Belgium. They found an average pollen count of 3.6 mg/m2 for the fertilised grasslands – 6.2 times higher than the unfertilised grasslands with 0.6 mg/m2 of pollen. The study also looked at how allergenic the pollen was by taking the blood of 20 people and exposing it to the pollen from the two types of grassland. When comparing the sensitivity of the participant's immune cells, they found on average that they were five times more sensitive to the pollen from the fertilised grasslands than the unfertilised grasslands. To confirm the allergy response, the authors said further research should expose participants themselves to pollen and then study their immune response. But they also said it highlights the need for more action on reducing nitrogen fertiliser use. 'In an era of ever-increasing nitrogen pollution worldwide, particularly in regions with intensive agricultural practices, our findings highlight the urgent need for integrated strategies to not only address its biodiversity and environmental impact but also the human health impact posed by nitrogen pollution,' they wrote. Roberto Picetti, assistant professor at the London School of Hygiene & Tropical Medicine (LSHTM), said: 'These findings are relevant to the UK, where nitrogen pollution remains a concern both in agricultural areas and in cities, and is already linked to other environmental and health problems, including respiratory illness, biodiversity loss, and air and water quality degradation. 'This study is a valuable step towards understanding and addressing the growing problem of pollen allergies and supports the case for more comprehensive environmental policies that consider both the health and ecological impacts of nitrogen pollution. 'By reducing nitrogen pollution, we could help protect biodiversity and lessen the severity of pollen allergies.' Roy Neilson, soil ecologist at The James Hutton Institute, said the authors take a 'novel approach of pollen assessment' in the study. 'The results of the study arguably support the importance of species-specific grass pollen monitoring given that a subset of grass species may have a disproportionate influence on respiratory health responses during peak grass pollen concentrations,' he said. 'However, it is unclear how a nitrogen-driven increase in pollen will contribute to the predicted increase in pollen season severity by up to 60% due to a changing climate.'
The Guardian
29-03-2025
- Science
- The Guardian
Mathematician Adam Kucharski: ‘Our concepts of what we can prove are shifting'
Adam Kucharski is a professor at the London School of Hygiene & Tropical Medicine. As a mathematician and epidemiologist, he has advised multiple governments on outbreaks such as Ebola and Covid. In his new book Proof: The Uncertain Science of Certainty, he examines how we can appraise evidence in our search for the truth. What inspired you to investigate the concept of proof?Alice Stewart, an influential epidemiologist, used this nice phrase that 'truth is the daughter of time'. But in many situations, whether you're accused of a crime or thinking about a climate crisis, you don't want to wait; there's an urgency to accumulate evidence and set a bar for action. We're entering an era where questions around information – what we trust and how we act – are increasingly important, and our concepts of what we can prove are shifting as well. You examined the ways that mathematical proofs have changed throughout history. What did you learn?I was so fascinated by the cultural differences in what people have assumed to be obvious. In Europe, for example, negative numbers were shunned for a very long time. That's because a lot of our maths was built around ancient Greek geometry, where something like a 'negative triangle' doesn't make sense. In contrast, a lot of the early mathematical theories in Asia were driven by finance and the concepts of debt, where negative numbers make a lot more sense, so they were much more comfortable handling those concepts. I found that ideas like calculus were also based on physical intuitions about the world: an apple falls, and we can write down the equations that drive its motion. But when you started getting down into it, you could find exceptions where the intuitions weren't true. As a result, you had this tension with an entire community who wanted to ignore these nuisances – these 'monsters', as they called them – while other characters were pushing for an evolution of the field. Einstein's work on relativity, for example, relied on these controversial ideas. In the book, you draw some parallels between these mathematical debates and the politics of the time.A lot of democratic ideas in the foundation of countries like the US attempted a kind of mathematical precision. The statement 'we hold these truths to be self-evident' in the US constitution was originally 'we hold these truths to be sacred', for example. But Benjamin Franklin crossed it out because he wanted more mathematical certainty behind these ideas, as if they were axioms. And in parallel with mathematics crumbling in its foundations, you saw the US descending into civil war, because the idea that all people are created equal wasn't self-evident to some people. You had the same tension manifesting in two different ways in two very different fields. Tell me a bit about Abraham Lincoln. How was he influenced by mathematics in his rhetoric?Lincoln was renowned for his speeches and the precise nature of his arguments, and that didn't come about by coincidence. He made a conscious decision as a lawyer to get a better understanding of what it means to demonstrate something and construct an argument that is logically robust. So he went and taught himself the fundamentals of ancient Greek mathematics, Euclid's Elements, and he would deploy those principles in his debates. He took advantage of this notion that if you can find a flaw or contradiction, you can cause someone's entire argument to collapse. You describe how some core concepts arose from casual conversations. How did the perfect cup of tea inspire the design of clinical trials?There was a tearoom in Rothamsted agricultural station in Hertfordshire, and in the early 1920s, three statisticians were having a conversation when one of them, Muriel Bristol, observed that tea always tastes better if the milk is put in before the hot water. The other people around the table disagreed, but they thought it was a nice challenge to see how you could work out whether she could tell the difference or not. In the end, they calculated that you need to lay out eight cups, in which half have the milk added before the hot water, and half after, ordered randomly. This produces around 70 possible combinations, meaning there is only a 1.4% chance that Bristol would get that out of all the possibilities correct – which she did. One of the mathematicians was Ronald Fisher, who would end up writing a landmark book called The Design of Experiments that examined how you can separate an effect from chance or human biases – and this included the principle of randomisation and using probabilities to test the strength of a hypothesis. How is AI changing our understanding of proof?A few years ago, I was at a dinner with a lot of AI specialists, and there was a lot of talk about the fact that AI is often more efficient if you don't worry about it providing an explanation for what it's doing or the decisions it makes. I found it interesting that this was a concern, because in medicine, we have a lot of things that work without us understanding why. One example is anaesthesia: we know the combination of drugs that makes a patient unconscious, but it's not clear why they do. We've struggled with similar questions for a long time, right?In the 1970s, we had the first ever computer-aided proof of the four-colour theorem, which says that if you want to colour a map so that no two bordering countries have the same colour, you'll only need four colours to do this. Even if you simplify it down and you look for symmetries, there are still just too many combinations to go through by hand. But a pair of mathematicians used a computer to punch those combinations and get over the line. There was a lot of scepticism, because it was the first time that you had this major theorem that mathematicians couldn't verify by hand. But then, among the younger generation of mathematicians, there is scepticism about some of the old methods. Why would hundreds of pages of handwritten maths be more trustworthy than a computer? I think that's going to be an important debate in the future, as algorithms become increasingly useful for the predictions they can make, even if we don't have an easy understanding of the way they work. With the spread of misinformation, it may feel that many people have simply stopped caring about evidence. What do you think of this?There has been some interesting research looking at what people say they value online, versus what they actually do. If you ask people whether accuracy is important in what they share, they'll say they don't want to share things that are false. In the moment, however, they often get distracted: something triggers an emotional response, or aligns with political beliefs, and they share the information on those grounds, without checking the facts. But there are lots of layers to this. In some cases, there can be an incentive to go against what authority says, if you want to suggest that you're not constrained by the thinking of the crowd. Henri Poincaré, a mathematician who did a lot of work in the late 19th and early 20th centuries, described something like this: 'To doubt everything or to believe everything are two equally convenient solutions; both dispense with the necessity of reflection.' And I think that's the danger, at the moment – that there's this almost excessive doubt. People are just disengaging with truth altogether. Proof: The Uncertain Science of Certainty by Adam Kucharski is published by Profile (£22). To support the Guardian and Observer order your copy at Delivery charges may apply
Yahoo
12-02-2025
- Business
- Yahoo
'Twitter Quitters' Help Push Bluesky User Base to Over 31 Million
The social network Bluesky has been growing at a rapid rate ever since the 2024 US presidential election concluded. The site has added over 14 million users since the November election, pushing it to over 31 million users by Feb. 11. Star Wars star Mark Hamill joined the site, proclaiming himself a "Twitter quitter." And Rep. Alexandria Ocasio-Cortez of New York became the first person to reach over 1 million followers on the platform. That's the first for any Bluesky account except the company's own. Ocasio-Cortez now has 1.7 million followers. There are at least two ever-changing counters created by Bluesky users that track the site's numbers. One counter is from Theo Sanderson, a professor at the London School of Hygiene & Tropical Medicine; another counter is by a user who simply goes by Natalie on the site. Read more: Bluesky Starter Packs: How to Find and Create Them A representative for the company said in an email last month that the site had added over 1 million users a day in the period immediately after the election. That rate equals about 12 new users per second. The 31 million user mark compares to 9 million users in September. Bluesky may be surging, but the site has a way to go to catch competing sites. Forbes reports that X has 588 million global users as of September, a drop from 611 million in April. Threads, Meta's competitor to X, has more than 275 million daily users. Although there's no way to determine how many new users left because of X owner Elon Musk's public support for President Donald Trump, many Bluesky users referenced the election in their first posts. Wired reports that many Taylor Swift fans, a group that once had a large presence on X, are switching to Bluesky. Bluesky is a social media platform that shares many similarities with X, formerly known as Twitter. X underwent a number of changes after billionaire Musk bought the site and retired legacy blue check marks showing verified accounts, reinstated previously banned accounts and started a new subscription program. On Oct. 16, X announced that it was changing its block function, which allowed people to stop others from seeing their messages on the site. Accounts that have been blocked can now see that person's posts on X if the posts are set to public, though they cannot reply, like or repost them. "That's not blocking," one X user replied. "That's supporting stalking." The following day, Oct. 17, Bluesky shared a post announcing that it had welcomed 500,000 people in just one day. "First day here," one Bluesky user wrote in response to the company's post about its growth. "Just getting my feet wet. Was a longtime Twitter user but it's a shell of what it used to be." X has also updated its terms of service so that any lawsuits by users against the service must be handled by a federal court in north Texas "whose judges frequently deliver victories to conservative litigants in political cases," The Globe and Mail reports. These latest changes may have sparked the rise of interest in Bluesky, which saw a surge in user accounts earlier this year when X was blocked by courts in Brazil (the block was later lifted when X paid a fine). According to The New York Times, users say Bluesky is the app that comes closest to mimicking X. Read more: Bluesky Is the Small Comfort I'd Been Looking For. Let's Hope It Lasts Here's a look at what you need to know about Bluesky. To join, just go to the main page to create an account. You can download the Bluesky app for iOS or Android, or use Bluesky on your desktop. It'll ask for your email address and phone number (to send an authentication code) and tell you to choose a username and password. Then you're in. If you're accustomed to X, Bluesky's design and purpose should make sense to you. The site uses vertically scrolling messages with small round photo avatars for users and icons under messages showing how many comments, likes and reposts they've received. It looks pretty similar to X's format and Meta's Threads, which is the current No. 2 free app on the App Store, behind Bluesky. Read more: Time to Cut Off Your X (Twitter)? Here's How Here's another Twitter/X connection: Twitter co-founder Jack Dorsey was formerly on the board of directors, and the Bluesky project began in 2019 when he was Twitter CEO. Jay Graber is the Bluesky CEO. Even Bluesky's name is related to X's former name. Dorsey confirmed a Bluesky user's speculation that the name ties in to Twitter's bird mascot, the idea being the bird could fly even more freely in an open blue sky. Dorsey left the board in May, apparently because the service added moderation tools. Even though the name of the site doesn't capitalize the S in "sky," it's pronounced "blue sky." Don't rhyme it with "brewski." The app is built on something called the authenticated transport protocol, or AT, a social media framework created by the company and made up of a network of many different sites. For one thing, you can set your domain as your handle, if you wish. This could help with verification, which became a heated issue for Twitter once Musk began removing blue check marks from verified accounts that refused to pay a monthly fee. "For example, a newsroom like NPR could set their handle to be @ the Bluesky Social company blog notes. "Then, any journalists that NPR wants to verify could use subdomains to set their handles to be @ Brand accounts could set their handle to be their domain as well." Moderation is also different. Another blog post says that Bluesky is already using automated moderating, and has a system of community labeling, which is described as "something similar to shared mute/block lists." Users of many social media platforms are shown posts from a feed selected for them by an algorithm, though you can influence that by following or blocking certain accounts. But Bluesky wants to give you a chance to pick from a variety of different algorithms to determine what you see. You can mute accounts, which prevents you from seeing any notifications or top-level posts from them, or you can block accounts, which takes that a step further, meaning you and the other account both cannot see or interact with each other's posts. And you can report posts or accounts for abuse. The blocking option may be of special interest to users who were unhappy with X's recent change in its blocking behavior. A couple of features -- being able to hide replies to your posts and detach your posts from other users' posts that quote yours -- are designed to stop pile-ons and other toxic behavior. It's possible that creators who acquire a following on Bluesky might one day be able to keep connections with those who follow them, even if the service itself changes. If you want to follow the people you followed on X, the third-party Sky Follower Bridge is a free tool that scans your follower list and follows accounts with the same names on Bluesky. You'll get a few false positives and a lot of dormant Bluesky accounts, but overall we've found it works very well. Algorithms are the rules that determine how content is filtered and recommended to users. Bluesky has something it calls custom feeds, which allows you to choose the algorithm that determines what you see. "Imagine you want your timeline to only be posts from your mutuals, or only posts that have cat photos, or only posts related to sports -- you can simply pick your feed of choice from an open marketplace," a blog post on the site says. A longer post goes into more detail about custom feeds and algorithmic choice. Click the hashtag icon on the bottom of the app to add and discover new feeds. Developers can use the site's feed generator starter kit to create a custom feed, and the site promises that eventually, the tools will be easy enough that the rest of us can build custom feeds. Want to jump right in to Bluesky by following a curated list of people? You can follow starter packs, which are lists created by users and usually themed. CNET has a lengthy explanation here, but in short, they're similar to what X calls lists, and are a good way to get a solid feed going that caters to your interests. Read more: It's Easy to Find Your X (Twitter) Favorites on Bluesky. Here's How to Do It Here's a small list of some of the people and groups you'll see posting on Bluesky. Star Wars star Mark Hamill Rep. Alexandria Ocasio-Cortez Pop legend Dionne Warwick Singer Lizzo Actor Ben Stiller Movie director Guillermo del Toro The X personality who goes by dril (real name: Paul Dochney) US Senator for Minnesota Tina Smith Author Stephen King Humor site The Onion Original EGOT Barbra Streisand Star Trek star George Takei 17th-century diarist Samuel Pepys Web cartoonist Randall Monroe, aka XKCD Author Colson Whitehead WWW inventor Tim Berners-Lee Actor and game-show host Drew Carey Author and Defector writer Drew Magary The New York Times Sci-fi author William Gibson God Oh, and CNET The National Football League is not a presence on Bluesky at the moment, and neither are its individual teams. Read more: Why You Won't See the NFL on Bluesky But that might change. The Sports Business Journal reports that the league is waiting to see if it can cut a deal with the service, and then you could see your favorite teams show up there.
Yahoo
27-01-2025
- Health
- Yahoo
Global warming to prevent 3.4 million deaths from cold ... but at a deadly cost
Global warming will prevent 3.4 million deaths from the cold in Europe by the end of the century, but excess heat will claim millions of lives on the Continent, new figures show. A stark north-south divide has emerged, as data show northerly European countries – including Britain – would see an overall mortality benefit from rising temperatures, while central and southern areas will face devastating consequences. Modelling of 854 cities by the London School of Hygiene & Tropical Medicine (LSHTM) shows that unmitigated warming would prevent about 630,000 deaths in Britain cumulatively by 2099. In contrast, heat would kill about 360,000 – leaving a net benefit of some 270,000 lives saved. Likewise, Denmark, Estonia, Finland, Ireland, Lithuania, Latvia and Norway would have more lives saved by preventing cold weather deaths than they lose from rising temperatures. However, countries including Italy, Spain and France would face hundreds of thousands of excess deaths, even after taking into account those people saved from the cold. Overall, researchers calculated that there would be about 5.8 million deaths in Europe because of unmitigated warming by the end of the century, with 3.4 million cold-weather deaths avoided – equating to about 2.3 million excess deaths overall. Commenting on the research, Prof Tim Osborn, director of the Climatic Research Unit at the University of East Anglia, said: 'Cold weather and hot weather kill tens of thousands of people across Europe every year. 'The harm from climate change impacts people very unevenly in this case, with far greater increases in temperature-related deaths predicted for southern Europe than for northern Europe, where milder winters may even reduce the number of deaths.' The same groups of people are generally at risk from both extreme cold and extreme heat, such as older adults and people with health conditions. Modelling showed that most cities in Britain and Scandinavian countries would have a net decrease in deaths. For example, London would have about 27,000 fewer deaths, Edinburgh would save 2,400, Belfast 1,908 and Cardiff 2,021. However, researchers said the lower death toll would be massively outweighed by the increases in the rest of Europe, particularly in populous Mediterranean cities. Barcelona would be the worst hit with 246,082 more deaths, followed by Rome and Naples at about 147,000 and Madrid with nearly 130,000 excess deaths by 2099. Pierre Masselot, lead author of the study from LSHTM, said: 'Our results stress the urgent need to aggressively pursue both climate change mitigation and adaptation to increased heat. 'This is especially critical in the Mediterranean area where, if nothing is done, consequences could be dire.' The figures were based on temperature projections coupled with population data and death estimates as a result of extreme conditions. Experts said that up to 70 per cent of the deaths could be prevented if rapid action was taken to adapt cities to changing temperatures, such as increasing green spaces, or implementing early warning systems. Garyfallos Konstantinoudis, a lecturer at Imperial College London, added: 'Previous estimates based on historical data have suggested that for every heat-related death there are roughly 10 cold-related deaths. 'This raises important questions about the net impact of temperature changes due to anthropogenic climate change. 'This new study underscores a crucial point: without any adaptation to temperature, projections suggest that temperature-related deaths are likely to increase overall, with heat-related deaths surpassing cold-related ones.' Experts warned that the figures were likely to be higher because the cities studied accounted for about 40 per cent of people in each country. The research was published in the journal Nature Medicine. Broaden your horizons with award-winning British journalism. Try The Telegraph free for 1 month with unlimited access to our award-winning website, exclusive app, money-saving offers and more.
The Guardian
27-01-2025
- Health
- The Guardian
Dangerous temperatures could kill 50% more Europeans by 2100, study finds
Dangerous temperatures could kill 50% more people in Europe by the end of the century, a study has found, with the lives lost to stronger heat projected to outnumber those saved from milder cold. The researchers estimated an extra 8,000 people would die each year as a result of 'suboptimal temperatures' even under the most optimistic scenario for cutting planet-heating pollution. The hottest plausible scenario they considered showed a net increase of 80,000 temperature-related deaths a year. The findings challenge an argument popular among those who say global heating is good for society because fewer people will die from cold weather. 'We wanted to test this,' said Pierre Masselot, a statistician at the London School of Hygiene & Tropical Medicine and lead author of the study. 'And we show clearly that we will see a net increase in temperature-related deaths under climate change.' The study builds on previous research in which the scientists linked temperature to mortality rates for different age groups in 854 cities across Europe. They combined these with three climate scenarios that map possible changes in population structure and temperature over the century. In all three scenarios, they found, uncomfortable temperatures will kill more people than they do today. The scientists cautioned that the uncertainties in the data are large. The net death toll is set to rise the most in hot southern Europe, particularly around the Mediterranean, with a second hotspot in central Europe that covers Switzerland, Austria and parts of southern Germany and Poland. Cool northern Europe, meanwhile, is expected to see a small decrease in deaths. 'In Norway, for instance, we might see a very slight benefit,' said Masselot. '[But this] is completely overshadowed by this massive increase we see in southern countries.' Heat and cold are silent killers that hurt the body well before they reach extremes that cause hypothermia and heatstroke. Excess mortality rates soar during heatwaves, particularly among people who are old or sick, as hot weather forces their bodies into overdrive and stops them from resting. Cold spells raise blood pressure and contribute to a range of heart and lung problems. 'Put bluntly, the increase in hot weather will kill more people than the decrease in cold weather will save,' said Tim Osborn, a climate scientist at the University of East Anglia, who was not involved in the research. 'While this new study isn't the final say on the matter … it does break new ground by scrutinising people's vulnerability to extreme temperatures by age and by city to a much better level of detail than previous work.' The analysis, which was limited to European cities, did not consider rural regions, which are less exposed to the urban heat island effect, or other parts of the planet, where heat is a more pressing problem. In total, they estimated the high warming scenario would lead to an extra 2.3 million people dying from dangerous temperatures in Europe between 2015 and 2099. Madeleine Thomson, a climate and health expert at research charity Wellcome, said the death toll was just one of the dangers of rising temperatures. 'Extreme heat kills but it also causes a wide range of serious health problems. It has been linked to an increased risk of cardiovascular disease, miscarriages and poor mental health.' Climate sceptics have argued against cutting pollution on the grounds that global warming will save lives, because cold kills more people than heat. Climate scientists say the different response rates to changes in temperature mean that heat deaths will grow much faster than cold deaths will fall, particularly at higher temperatures. 'There are also legitimate arguments that this net effect is only of limited relevance,' said Erich Fischer, a climate scientist at the Swiss Federal Institute of Technology in Zurich (ETHZ), who was not involved in the study. 'If a new drug with serious side effects that lead to countless deaths were approved, I would hardly argue that the drug saves about as many lives, or that the net effect could even be slightly positive in the short term despite the many deaths.' The study explored how lives could be saved if people adapted to the changes in temperature and reduced their exposure to uncomfortable temperatures. In the hottest scenario, only 'implausibly strong' levels of adaptation could halt the trend of rising net deaths, the study found. In scenarios that cut carbon pollution, a 50% drop in temperature exposure was enough for net deaths to drop. 'The good news is that we can adapt,' said Víctor Resco de Dios, an environmental engineer at the University of Lleida, who was not involved in the study. 'Adaptation starts with relatively simple solutions – although they are not free – such as installing air conditioning or creating spaces that serve as climate shelters.' 'But we must also address more complex solutions – such as increasing green areas in cities to mitigate the urban heat island – and adapting health systems,' he added.
