34 million Americans reside in sinking urban areas, expert issues
The study, conducted by Columbia University, found that while coastal cities are at risk, some of the areas sinking fastest were actually landlocked cities such as Fort Worth and Dallas. But coastal Houston is the fastest-sinking city in the country, with almost half of its area dipping more than one fifth of an inch per year. Some spots are sinking even faster — up to 2 inches per year.
Dallas and Fort Worth aren't far behind, sinking at rates of roughly 0.16 and 0.2 inch per year, respectively. The study also highlighted New York's LaGuardia Airport, parts of Las Vegas, Washington DC and San Francisco as rapidly sinking zones. The 28 cities are home to nearly tens of millions of people, and more than 60 percent if this total population lives in just eight cities: New York, Chicago, Los Angeles, Phoenix, Houston, Philadelphia, San Antonio and Dallas.
The researchers note that these cities have seen more than 90 major floods within the last 25 years, and suggest that this is due in large part to the fact that they're sinking. 'As cities continue to grow, we will see more cities expand into subsiding regions,' said lead author Leonard Ohenhen, a postdoctoral researcher at the Columbia Climate School's Lamont-Doherty Earth Observatory. 'Over time, this subsidence can produce stresses on infrastructure that will go past their safety limit,' he added. Ohenhen and his colleagues used satellite data to map sinking down to the millimeter in all US cities with populations over 600,000.
They also looked at the amount of groundwater pumping in affected counties and linked it to ground sinking. Coastal cities tend to be more prone to ground sinking due to the combined effects of groundwater pumping and sea level rise. But multiple interior cities, such as Denver, Oklahoma City and Nashville, are experiencing moderate sinking. Those three are sinking roughly 0.04 to 0.08 inch per year.
About one percent of land in the 28 cities is experiencing sinking that could impact critical infrastructure such as buildings, roads and rail lines. Even though that percentage seems small, these areas tend to be located in the densest parts of these cities, which contain up to 29,000 buildings. From this perspective, the most hazardous cities are San Antonio, where one in 45 buildings are at 'high risk' of damage from ground sinking, Austin, Fort Worth, and Memphis.
Across the US, and in interior cities especially, ground sinking is mainly driven by groundwater pumping, the researchers concluded. When water is extracted from aquifers made up of saturated fine-grained sediments and not replenished, the pore spaces between the sediment particles can collapse. This causes the lower layers of the aquifer to condense and become compacted, and results in sinkage at the surface, according to the researchers.
In Texas, this is made even worse by oil and gas drilling, they explained in their report. And there are other factors at play too. Roughly 20,000 years ago, interior North America was covered by a towering ice sheet that made the land along its edges bulge upward. That ice sheet is long gone, but some of the bulges still exist, though they are subsiding at rates of 0.04 to 0.12 inch per year.
This is adding to ground sinking observed in New York City, Indianapolis, Nashville, Philadelphia, Denver, Chicago and Portland, according to the researchers. The team published their findings in the journal Nature Cities on Tuesday. A 2023 study also found that the weight of buildings in densely urbanized areas may be contributing to ground sinking.
Those researchers found that New York's more than one million buildings are pressing down on the Earth so hard that they have become an important factor in the city's subsidence. New construction may be playing a role too. A more recent study found that some buildings in Miami are sinking in part due to subsurface disruptions caused by buildings going up nearby. The researchers urge cities to use their data to develop mitigation strategies for ground sinking and flood risk.
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The Guardian
an hour ago
- The Guardian
Can you see circles or rectangles? And does the answer depend on where you grew up?
Do people from different cultures and environments see the world differently? Two recent studies have different takes on this decades-long controversy. The answer might be more complicated, and more interesting, than either study suggests. One study, led by Ivan Kroupin at the London School of Economics, asked how people from different cultures perceived a visual illusion known as the Coffer illusion. They discovered that people in the UK and US saw it mainly in one way, as comprising rectangles – while people from rural communities in Namibia typically saw it another way: as containing circles. To explain these differences, Kroupin and colleagues appeal to a hypothesis raised more than 60 years ago and argued about ever since. The idea is that people in western industrialised countries (these days known by the acronym 'weird' – for western, educated, industrialised, rich and democratic – a summary that is increasingly questionable) see things in a specific way because they are generally exposed to highly 'carpentered' environments, with lots of straight lines, right angles – visual features common in western architecture. By contrast, people from non-'weird' societies – like those in rural Namibia – inhabit environments with fewer sharp lines and angular geometric forms, so their visual abilities will be tuned differently. The study argues that the tendency of rural Namibians to see circles rather than rectangles in the Coffer illusion is due to their environments being dominated by structures such as round huts instead of angular environments. They back up this conclusion with similar results from several other visual illusions, all supposedly tapping into basic brain mechanisms involved in visual perception. So far, so good for the cross-cultural perceptual psychologists, and for the 'carpentered world' hypothesis. The second study, by Dorsa Amir and Chaz Firestone, takes a sledgehammer to this hypothesis, but for the much better-known illusion: the Müller-Lyer illusion. Two lines of equal length seem to be different lengths because of the context provided by inward-pointing, compared with outward-pointing, arrowheads. It's a very powerful illusion. I've seen it on thousands of occasions and it works every time for me. There are many explanations for why the Müller-Lyer illusion is so effective. One of the more popular is that the arrowheads are interpreted by the brain as cues about three-dimensional depth, so our brains implicitly interpret the illusion as representing an object of some kind, with right angles and straight lines. This explanation fits neatly with the 'carpentered world' hypothesis – and indeed a lot of early support for this hypothesis relied on apparent cultural variability in how the Müller-Lyer illusion is perceived. In their study, Amir and Firestone carefully and convincingly dismantle this explanation. They point out that non-human animals experience the illusion, as shown in a range of studies in which animals (including guppies, pigeons and bearded dragons) are trained to prefer the longer of two lines, and then presented with the Müller-Lyer image. They show that it works without straight lines, and for touch as well as vision. They note that it even works for people who until recently have been blind, referencing an astonishing experiment in which nine children, blind from birth because of dense cataracts, were shown the illusion immediately after the cataracts were surgically removed. Not only had these children not seen highly carpentered environments – they hadn't seen anything at all. After you absorb their analysis, it's pretty clear that the Müller-Lyer illusion is not due to culturally specific exposure to carpentry. Why the discrepancy? There are several possibilities. Perhaps there are reasons why cross-cultural variability should be expected for the Coffer but not the Müller-Lyer illusion (one possibility here is that the Coffer illusion is based on how people pay attention to things, rather than on some more basic aspect of perception). It could also be that there are systematic differences in perception between cultures, but that the 'carpentered world' hypothesis is not the correct explanation. It's also worth noting that the Kroupin study has some potential weaknesses. For example, the UK/US and Namibian participants were exposed to the illusions using very different methods. All in all, the jury remains out and – favourite scientist punt coming up – 'more research is needed'. The notion that people from different cultures vary in how they experience things is certainly plausible. There's a wealth of evidence that as we grow up our brains are shaped, at least to some extent, by features of our environments. And just as we all differ in our externally visible characteristics – height, body shape and so on – we will all differ on the inside too. As the author Anaïs Nin put it in quoting the Talmud: 'We do not see things as they are, we see them as we are.' For me, an important implication of this line of thought is that there are likely to be substantial differences in perception within 'groups' as well as between them. This will probably hold however these 'groups' are defined, whether as different cultures or as a contrast between 'neurotypical' and 'neurodivergent' people. I believe that paying more attention to within-group perceptual diversity will help us to better interpret the differences we do find between groups, and equip us with the tools needed to resist relying on simple cultural stereotypes as explanations. More research is needed here too. But it's on the way. In the Perception Census, a project led by my research group at the University of Sussex together with professor Fiona Macpherson at the University of Glasgow, we are studying how perception differs in a large sample of about 40,000 people from more than 100 countries. Our experiment includes not just one or two visual illusions but more than 50 different experiments probing many different aspects of perception. When we're done analysing the data, we hope to deliver a uniquely detailed picture of how people experience their world, both within and between cultures. We'll also make the data openly available for other researchers to explore new ideas in this important area. One critical insight lies behind all these questions. How things seem is not how they are. For each of us, it might seem as though we see the world exactly as it is; as if our senses are transparent windows through with the world pours itself directly into our mind. But how things are is very different. The objective world no doubt exists, but the world we experience is always an active construction, a kind of 'controlled hallucination' in which the brain uses sensory signals to update and calibrate its best interpretation of what's going on. What we experience is this interpretation, not a 'readout' of the sensory information. For me, this is the key insight that underlies any claim about perceptual diversity. When we take it fully on board, it encourages a much-needed humility about our own ways of seeing. We live in perceptual echo chambers, just as we do in those of social media, and the first step to escaping any echo chamber is to realise that you're in one. Anil Seth is a professor of cognitive and computational neuroscience at the University of Sussex, and author of the Sunday Times bestseller Being You: A New Science of Consciousness
Telegraph
2 hours ago
- Telegraph
Forgetfulness or early dementia? How to decipher your memory loss
Illustrations by James Yates At some point, we've all strode into a room with purpose and proceeded to completely forget what we were about to do. 'It's a very common complaint,' confirms Prof Scott Small, director of the Alzheimer's Disease Research Centre at Columbia University, who has studied memory for more than three decades. It used to be thought that a forgetful blip like this served no purpose and was simply a malfunction in our memory machinery, but now we know otherwise. Our memory machinery comprises several stages: our short-term and long-term memory, as well as our ability to save and recall memories. Prof Small uses the analogy of a computer to explain how we remember and forget: 'If you type something into a document and don't save it, it's gone forever – that's your short-term memory,' he says. 'If you click save, that transfers information from the short-term memory to the long-term memory. 'The other function is to be able to come back to your computer, or brain, and recall what was talked about the day before. For this, you need to have the 'open' function to be able to sift through all your memories and choose the right one.' Rather than a glitch in this hardwiring, forgetting is a healthy and necessary part of our brain's normal functioning and is vital for our creativity and mental health, as Prof Small explains in his book Forgetting, The New Science of Memory. Not only does forgetting clear cognitive bandwidth and ensure our brains are not overwhelmed with irrelevant information, but 'emotional forgetting' is also necessary to move past traumatic experiences. Though, there is a catch. As well as normal forgetting, there is also what Prof Small refers to as 'pathological forgetting' – the type that we are right to worry about. Typically caused by neurodegenerative disorders, it indicates a worsening of memory that impacts our ability to live our life fully. 'If you notice worsening of your memory over time from your own baseline, that's probably pathological forgetting, such as Alzheimer's.' Here, Prof Small shares his expertise on common examples of forgetting to distinguish which fall into the normal category and which could be an early sign of Alzheimer's. 'However, the ultimate diagnosis is when you see a doctor,' he notes. I've gone upstairs and forgotten why 'That's a super common complaint,' Prof Small says. 'This symptom alone tells me that it's probably the hippocampus, as that's the structure of the brain that's critical for memory.' The hippocampus is the 'save' button on your computer, transferring information from temporary to long-term. 'If that's always happened to you, it's normal forgetting.' Like height and weight, normal forgetting is a trait that varies between us and it's nothing to worry about if it remains consistent. However, if you're increasingly catching yourself uncertain about what you're doing mid-task, it could be an early indicator of pathological forgetting, which can be a result of cognitive ageing (forgetting that occurs as part of the normal ageing process) or Alzheimer's, Prof Small says. 'This symptom alone is not enough for me to say whether it's the earliest stages of Alzheimer's or if it's just cognitive ageing,' he notes. 'A rule of thumb in medicine is, if you experience something that really disturbs your life, it might be worth seeing a doctor. But, on its own, forgetting why you've gone upstairs doesn't declare itself as a disorder that's worth seeing a doctor for.' I'm getting names mixed up If you've forgotten or mixed up the name of someone you met a couple of times many years ago, it's nothing to worry about, Prof Small says. If you've forgotten the name of a loved one as a one-off, it's also not a cause for concern. 'It may be a bad night's sleep or stress,' he notes. 'But if someone's frequently forgetting the names of loved ones, people in their inner circle, it's time to see a doctor,' he says. It indicates a memory problem and could be a sign of Alzheimer's, he says. Similarly, if you forget the name of your prime minister or president, that's more concerning than if you forget the name of your local MP, Prof Small says. I can't remember how to make my favourite recipe 'If someone forgets a recipe that they've been making over and over again, I'm starting to worry about a disease,' Prof Small says. 'It sounds like Alzheimer's.' The memory decline that occurs with age doesn't affect our memory 'hard drive', where we store key pieces of information that we use regularly, like a favourite recipe. However, Alzheimer's does. 'It spreads to areas of the memory store, memory retrieval and recall, while ageing does not,' Prof Small says. 'The example of the recipe sounds like Alzheimer's because it's not the 'save' function of our brain,' which is used for new memories, he notes. Instead, it signals a problem with the memory hard drive. I got lost on a route I've done a million times Whilst forgetting why you walked into a room or the name of someone you only vaguely know is likely innocuous, Prof Small says that getting lost is a sign of something more serious. 'If someone tells me that they've forgotten where they've parked their car or if they've gotten lost while driving to work, that's a red flag,' he says. 'I start thinking, maybe this is Alzheimer's.' One way to think about the hippocampus is as a circuit made up of different regions that are all interconnected, Prof Small explains. The area responsible for spatial memory is the region where Alzheimer's takes hold. 'So when I hear people complain about getting lost, I start thinking more about Alzheimer's disease,' he says. I asked my husband a question but can't remember the answer five minutes later Forgetting information that we've just been told happens to all of us, Prof Small says. It could be poor attention or, if it's always in relation to your husband, there could be psychological reasons why you're not focusing on what he's saying, he notes. As a result, this falls into normal forgetting but, if it's becoming more frequent, this could be a worrying symptom. What can we do to protect our memory? There are many risk factors that increase the risk of developing Alzheimer's and other forms of dementia, including obesity, poor heart health, high blood pressure and cholesterol and diabetes, Prof Small says. 'That doesn't mean these factors alone will cause Alzheimer's but, if you're going to get it, these may accelerate it,' he explains. In addition, there are certain genes that are associated with Alzheimer's, most famously Apolipoprotein E (APOE), and a family history also raises the risk. While these can't be changed, living a healthy lifestyle has been shown to benefit brain health and reduce the risk of dementia. 'Exercise seems to be a very strong influencer of maintaining our memory health into late life,' Prof Small notes. Meanwhile, his own research has found that eating a diet rich in flavanols, compounds found in apples, berries and tea, amongst other fruits and vegetables, also protects brain health. Scientists are also racing to find medicines to ward off memory-robbing diseases. 'Where we are in the field is trying to develop statins for the brain,' Prof Small says. To do that, researchers need to understand the mechanisms that are causing Alzheimer's, with the brain's immune network and system for moving proteins around our cells (known as the trafficking pathway) under investigation. So far, development has focused on drugs that work by clearing proteins called amyloid from the brain, which have been shown to disrupt neuron function. However, these have so far been blocked for use on the NHS due to their cost (estimated to be £30,000 per patient per course of treatment) and worries over side effects. 'The next generation of drugs are trying to target either the immune response or the trafficking pathway,' he explains. 'Once the biomedical enterprise has a target, where the field at large is so sophisticated, we should be optimistic that we will have a way to intervene,' Prof Small says. 'It could mean that in a year we'll have effective new drugs that target the pathways that I and others believe will be more beneficial than anti-amyloid drugs. It could take a few years but I don't think it's going to take decades. 'I think we're on the cusp of really translating all the remarkable discoveries that happened in the first 20 years of this century into meaningful therapeutics.'
The Guardian
5 hours ago
- The Guardian
Text therapy: study finds couples who use emojis in text messages feel closer
The secret to a good relationship may be staring smartphone users in the face. A new study published in the journal Plos One found that using emojis in text messages makes people feel closer and more satisfied in their personal lives. Researchers at the University of Texas spoke to 260 people aged between 23 and 67 and asked them to read 15 text message exchanges that varied only in the presence or absence of emojis. Participants were instructed to imagine themselves as the sender of each message while focusing on the recipient's replies to evaluate responsiveness, likability, closeness and relationship satisfaction. The study revealed that people who send emojis combined with text are seen to be more responsive in their relationships than people who send text alone. It also found emojis serve as nonverbal cues that signal attentiveness and emotional engagement. Luke McGregor, 42, and Amy Thunig-McGregor, 37, say being able to use emojis helps their family communicate better. Luke said he wasn't a regular emoji sender at the start of their relationship and had to learn to start incorporating them into text messages to Amy. 'I traditionally didn't use emojis that much but when I first got [together] with Amy, I noticed them using them a lot, so there was a vulnerability or a hurdle I had to get over to start using them myself,' McGregor said. 'I wanted Amy to know that they were loved, and so to become a regular sender of emojis to Amy in order to communicate affection was at least initially a big deal for me.' Amy said emojis were a good tool to enhance their communication. 'We're both autistic as well for context … it helps us really be clear with tone and intention in a way that isn't possible with just written text,' they said. Senior lecturer in psychology at Central Queensland University Dr Raquel Peel, who was not involved in the study, said sending emojis can be a creative alternative when people are unable to see their partner face to face. 'I don't think we can replace face-to-face interactions because we are talking about intimate partnerships and relationships, but we have to be realistic that this isn't always possible,' Peel said. 'So if you can't meet face to face with your partner for whatever reason staying connected is important. 'Using emojis is then an effective alternative.' Her advice was to not underestimate the value of communication in a relationship and to always try and stay connected to your partner in whatever way you communicate. 'One thing that people also forget when I'm talking to them about relationships is the value of humour and having a bit of fun,' Peel said. 'So if emojis can serve a purpose that way, which we know they can, it adds to the element of fun and connection through humour and that is really important.'
