It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Friday, June 13, 2025
Leg amputation caused by arterial disease four times higher in disadvantaged areas
Leg amputation caused by arterial disease four times higher in disadvantaged areas
A new study from the University of Sheffield highlights the scale of socioeconomic disparities in leg amputation caused by arterial disease across England
Lower limb amputation rates are four times as high in the most socioeconomically disadvantaged areas in England compared with the least disadvantaged areas
Peripheral arterial disease is a debilitating condition which is caused by a build-up of fatty deposits in the arteries to the legs which restricts blood supply
Findings show patients living in the most disadvantaged areas are also more likely to die following amputation
Leg amputation rates caused by arterial disease are four times as high in the most disadvantaged areas in England.
The new study, from the University of Sheffield, also found patients living in the most socioeconomically disadvantaged areas are more likely to die following leg amputation compared with those living in the least disadvantaged areas.
Whilst socioeconomic disadvantage is associated with a higher risk of amputation, this new study highlights the worrying scale of the disparities.
Peripheral arterial disease is a debilitating condition caused by a build-up of fatty deposits in the arteries to the legs which restricts blood supply. Major amputation of the lower limb is a last resort when other treatment options do not exist or have failed.
The main reasons for amputation include severe infection of the leg and gangrene caused by restricted arterial blood supply.
The new study, funded by the National Institute for Health and Care Research (NIHR), examined associations between socioeconomic deprivation and ethnicity and major leg amputation in England.
The researchers analysed hospital admissions and census area data over a 12-year period from 2006 to 2018. During the study period there were a total of 47,249 major lower limb amputations due to peripheral arterial disease.
The researchers found the main disparities were as a result of socioeconomic inequalities.
Above knee amputation was around four times as high in the most disadvantaged compared with the least disadvantaged areas, while below knee amputation was around three times as high.
Although amputation rates decreased in all socioeconomic categories from 2006 to 2018 in the population aged over 65 years, there was little change in the population under 65.
Professor Ravi Maheswaran, Emeritus Professor of Epidemiology and Public Health at the University of Sheffield’s School of Medicine and Population Health, said: “Being told you need to have a leg amputated can be a devastating and frightening experience for patients.
“Greater efforts are needed in socioeconomically disadvantaged areas in order to prevent and manage peripheral arterial disease, reduce amputation rates and improve survival following amputation.”
A new study from Toho University reveals that female earwigs exhibit a similar pattern of exaggerated forceps growth as males, suggesting that both sexes may have evolved these traits through sexual selection.
Do larger male elk have proportionally larger antlers? The answer is no. In fact, larger individuals tend to have disproportionately larger antlers—a phenomenon known as positive allometry. This pattern, where certain body parts grow disproportionately large relative to body size, is observed not only in mammals but also in animals such as beetles and fiddler crabs. Evolutionary biologists interpret such traits as evidence of sexual selection—a process in which physical features evolve because they offer an advantage in competing for mates.
Male earwigs are known to show positive allometry in their forceps—pincer-like appendages at the tip of the abdomen—which are believed to have evolved as weapons in battles with rivals. But what about females? Female earwigs also have forceps—so what purpose do they serve?
Tomoki Matsuzawa (then an undergraduate) and Associate Professor Junji Konuma from Toho University’s Department of Biology conducted the first quantitative study of female earwig forceps. Using morphometric analysis on the maritime earwigs Anisolabis maritima, they found that female forceps also display positive allometry—suggesting that they, too, may have evolved through sexual selection.
The team measured the head, thorax, abdomen, and bilateral forceps dimensions and analyzed shape differences in both sexes. They found that males have thick, short, and curved forceps, while females have thin, long, and straight ones—indicating clear sexual dimorphism. When they plotted body size against forceps width and length on a log–log scale, the results revealed a pattern of positive allometry in males: forceps width increased disproportionately with body size. Surprisingly, positive allometry was also found in females—in the length of the forceps. These results suggest that while the sexes differ in forceps shape, both may have evolved them as weapons—albeit in different ways.
Associate Professor Konuma explains:“A previous behavioral study has shown that female earwigs compete for small, non-aggressive males. Our findings suggest that female forceps may have evolved as effective weapons in such competition. While most earlier research focused only on males, our study highlights the importance of considering female traits as well when studying the evolution of insect morphologies.”
These findings were published on June 12, 2025, in the Biological Journal of the Linnean Society.
Among the tens of thousands of ant species, incredible ‘intelligent’ behaviors like crop culture, animal husbandry, surgery, ‘piracy’, social distancing, and complex architecture have evolved. Yet at first sight, the brain of an ant seems hardly capable of such feats: it is about the size of a poppy seed, with only 0.25m to 1m neurons, compared to 86bn for humans. Now, researchers from Israel and Switzerland have shown how ‘swarm intelligence’ resembling advance planning can nevertheless emerge from the concerted operation of many of these tiny brains. The results are published in Frontiers in Behavioral Neuroscience.
“Here we show for the first time that workers of the longhorn crazy ant can clear obstacles from a path before they become a problem – anticipating where a large food item will need to go and preparing the way in advance. This is the first documented case of ants showing such forward-looking behavior during cooperative transport,” said Dr Ehud Fonio, a research fellow at the Weizmann Institute of Science in Israel, and the corresponding author of the study.
‘I can see all obstacles in my way’
The researchers were inspired when they made a fascinating chance observation in nature: individual crazy ant workers used their mandibles to pick up and carry away tiny gravel pebbles near groups of workers cooperating to transport large insect prey.
“When we first saw ants clearing small obstacles ahead of the moving load we were in awe. It appeared as if these tiny creatures understand the difficulties that lie ahead and try to help their friends in advance,” said Dr Ofer Feinerman, a professor at the Weizmann Institute, and the study’s final author.
Fonio et al. designed a suite of 83 experiments to study this obstacle-clearing behavior on a single crazy ant ‘supercolony’ on the Weizmann Institute’s campus. For pebbles, they used plastic beads with a diameter of 1.5 millimeter (half the body length of the ants) to block the ants’ route. For prey, they used pellets of cat food, of which the ants are fond.
Triggered into clearing mode by pheromones
Like many ant species, crazy ants are known to alert their sisters to the presence of large food items by laying odor trails: running erratically (hence their ‘crazy’ name), they touch the ground with the tip of their abdomen every 0.2 seconds to deposit a tiny droplet of a pheromone. This pheromone swiftly attracts other workers to the food. But here, the scientists found this pheromone to play a key role in clearing behavior as well.
Their observations showed that workers were most prone to clear beads that lay approximately 40mm away from food towards the direction of the nest. They moved these beads for up to 50mm before dropping them, away from the route leading back to the nest. The record holder cleared 64 beads in succession.
Such clearing behavior always occurred when the pellet was whole, but rarely when it was divided into crumbs. This distinction seemed adaptive, as the observations showed that crumbs were always carried home by single workers, who would simply walk around any beads in their path. Intact pellets, however, always prompted ‘cooperative’ transport by multiple workers, who typically remained stalled by a grid of beads until these were cleared.
That the beads were a real hindrance was also clear from the time that cooperative transport took to pass through a 5cm by 7cm tunnel: this was 18 times longer when the passage was filled with beads than when it was free of obstacles.
Further observations also revealed that workers didn’t need to be in contact with the food to start clearing behavior: they were prompted to do so by pheromones deposited by foragers. A single mark that happened to be near a bead was sufficient to put a worker in ‘clearing mode’, after which they would actively look for more beads to clear.
‘Awe-inspiring’
“Taken together, these results imply that our initial impression was wrong: in reality, individual workers don’t understand the situation at all. This intelligent behavior happens at the level of the colony, not the individual. Each ant follows simple cues – like fresh scent marks left by others – without needing to understand the bigger picture, yet together they create a smart, goal-directed outcome,” concluded Dr Danielle Mersch, formerly a postdoctoral researcher at the same institute.
“We find this to be even more awe-inspiring than our initial guess,” said Feinerman.
“Humans think ahead by imagining future events in their minds; ants don’t do that. But by interacting through chemical signals and shared actions, ant colonies can behave in surprisingly smart ways – achieving tasks that look planned, even though no single ant is doing the planning. These ants thus provide us an analogy to brains, where from the activity of the relatively simple computational units, namely neurons, some high cognition capabilities miraculously emerge.”
Ants engaged in cooperative food transport show anticipatory and nest-oriented clearing of the obstacles surrounding the food: goal-directed behavior emerging from collective cognition
Article Publication Date
13-Jun-2025
AI-enabled control system helps autonomous drones stay on target in uncertain environments
The system automatically learns to adapt to unknown disturbances such as gusting winds
Cambridge, MA – An autonomous drone carrying water to help extinguish a wildfire in the Sierra Nevada might encounter swirling Santa Ana winds that threaten to push it off course. Rapidly adapting to these unknown disturbances inflight presents an enormous challenge for the drone’s flight control system.
To help such a drone stay on target, MIT researchers developed a new, machine learning-based adaptive control algorithm that could minimize its deviation from its intended trajectory in the face of unpredictable forces like gusty winds.
Unlike standard approaches, the new technique does not require the person programming the autonomous drone to know anything in advance about the structure of these uncertain disturbances. Instead, the control system’s artificial intelligence model learns all it needs to know from a small amount of observational data collected from 15 minutes of flight time.
Importantly, the technique automatically determines which optimization algorithm it should use to adapt to the disturbances, which improves tracking performance. It chooses the algorithm that best suits the geometry of specific disturbances this drone is facing.
The researchers train their control system to do both things simultaneously using a technique called meta-learning, which teaches the system how to adapt to different types of disturbances.
Taken together, these ingredients enable their adaptive control system to achieve 50 percent less trajectory tracking error than baseline methods in simulations and perform better with new wind speeds it didn’t see during training.
In the future, this adaptive control system could help autonomous drones more efficiently deliver heavy parcels despite strong winds or monitor fire-prone areas of a national park.
“The concurrent learning of these components is what gives our method its strength. By leveraging meta-learning, our controller can automatically make choices that will be best for quick adaptation,” says Navid Azizan, who is the Esther and Harold E. Edgerton Assistant Professor in the MIT Department of Mechanical Engineering and the Institute for Data, Systems, and Society (IDSS), a principal investigator of the Laboratory for Information and Decision Systems (LIDS), and the senior author of a paper on this control system.
Azizan is joined on the paper by lead author Sunbochen Tang, a graduate student in the Department of Aeronautics and Astronautics, and Haoyuan Sun, a graduate student in the Department of Electrical Engineering and Computer Science. The research was recently presented at the Learning for Dynamics and Control Conference.
Finding the right algorithm
Typically, a control system incorporates a function that models the drone and its environment, and includes some existing information on the structure of potential disturbances. But in a real world filled with uncertain conditions, it is often impossible to hand-design this structure in advance.
Many control systems use an adaptation method based on a popular optimization algorithm, known as gradient descent, to estimate the unknown parts of the problem and determine how to keep the drone as close as possible to its target trajectory during flight. However, gradient descent is only one algorithm in a larger family of algorithms available to choose, known as mirror descent.
“Mirror descent is a general family of algorithms, and for any given problem, one of these algorithms can be more suitable than others. The name of the game is how to choose the particular algorithm that is right for your problem. In our method, we automate this choice,” Azizan says.
In their control system, the researchers replaced the function that contains some structure of potential disturbances with a neural network model that learns to approximate them from data. In this way, they don’t need to have an a priori structure of the wind speeds this drone could encounter in advance.
Their method also uses an algorithm to automatically select the right mirror-descent function while learning the neural network model from data, rather than assuming a user has the ideal function picked out already. The researchers give this algorithm a range of functions to pick from, and it finds the one that best fits the problem at hand.
“Choosing a good distance-generating function to construct the right mirror-descent adaptation matters a lot in getting the right algorithm to reduce the tracking error,” Tang adds.
Learning to adapt
While the wind speeds the drone may encounter could change every time it takes flight, the controller’s neural network and mirror function should stay the same so they don’t need to be recomputed each time.
To make their controller more flexible, the researchers use meta-learning, teaching it to adapt by showing it a range of wind speed families during training.
“Our method can cope with different objectives because, using meta-learning, we can learn a shared representation through different scenarios efficiently from data,” Tang explains.
In the end, the user feeds the control system a target trajectory and it continuously recalculates, in real-time, how the drone should produce thrust to keep it as close as possible to that trajectory while accommodating the uncertain disturbance it encounters.
In both simulations and real-world experiments, the researchers showed that their method led to significantly less trajectory tracking error than baseline approaches with every wind speed they tested.
“Even if the wind disturbances are much stronger than we had seen during training, our technique shows that it can still handle them successfully,” Azizan adds.
In addition, the margin by which their method outperformed the baselines grew as the wind speeds intensified, showing that it can adapt to challenging environments.
The team is now performing hardware experiments to test their control system on real drones with varying wind conditions and other disturbances.
They also want to extend their method so it can handle disturbances from multiple sources at once. For instance, changing wind speeds could cause the weight of a parcel the drone is carrying to shift in flight, especially when the drone is carrying sloshing payloads.
They also want to explore continual learning, so the drone could adapt to new disturbances without the need to also be retrained on the data it has seen so far.
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This research was supported, in part, by MathWorks, the MIT-IBM Watson AI Lab, the MIT-Amazon Science Hub, and the MIT-Google Program for Computing Innovation.
Study suggests that appetite for bushmeat – rather than black market for scales to use in traditional Chinese medicine – may be driving West Africa’s illegal hunting of one of the world’s most threatened mammals.
Interviews with hundreds of hunters show pangolins overwhelmingly caught for food, with majority of scales thrown away. Survey work shows pangolin is considered the most palatable meat in the region.
The vast majority of pangolin hunting in African forest landscapes is done for meat consumed by people in the region, rather than for scales shipped to East Asia, a new study led by the University of Cambridge suggests.
Pangolins are the most heavily trafficked wild mammal in the world. A solitary, insect-eating animal about the size of a large domestic cat*, pangolins are famous for their highly prized keratin scales – a staple of traditional Chinese medicine.
All eight existing pangolin species are threatened with extinction and on the IUCN’s Red List, with three Asian species categorised as critically endangered.
As Asian pangolins have declined dramatically, Nigeria has seen a boom in the export of pangolin scales to Asia. While hunting pangolins is illegal in Nigeria the West African country is now the world’s largest hub for the criminal trade in pangolin products.
However, a new study published in the journal Nature Ecology & Evolution suggests that some 98% of Nigerian pangolins are caught for meat first and foremost, with around two-thirds of scales from these animals simply thrown away.
A research team led by Cambridge collected data from over eight hundred hunters and traders in thirty-three locations across Nigeria’s Cross River Forest region, primarily between 2020 and 2023, during which time the conservationists estimate that around 21,000 pangolins were killed annually in the area.
Almost all pangolins were captured “opportunistically” or during general hunting trips (97%) rather than sought out, and caught primarily for meat (98%). Around 71% of pangolins were consumed by hunters themselves, with 27% traded locally as food.
Perhaps surprisingly, given their potential overseas value, around 70% of the scales were discarded, while less than 30% were sold on. However, researchers calculated that, per animal, pangolin meat fetched 3-4 times the price of scales at local Nigerian markets.
“Thousands of kilos of pangolin scales are seized at Nigeria’s ports, creating the impression that the international demand for scales is behind pangolin exploitation in West Africa,” said study lead author and Gates Cambridge Scholar Dr Charles Emogor, who conducted the research for his PhD at the University of Cambridge’s Department of Zoology.
“When we spoke to hunters and traders on the ground around the Cross River forest, the largest stronghold for Nigeria’s pangolins, it was obvious that meat was the motivation for almost all of the pangolin killings.”
“We found that dedicated pangolin hunts are virtually non-existent. Most pangolins are killed by hunters out for any type of game,” said Emogor, now a Schmidt Science Fellow split between Cambridge, UK, and Harvard, US.
“Around a third of pangolins are caught opportunistically, often while people are working in the fields. Pangolins curl into a ball when threatened, which sadly makes them easy to catch.” Among frequent hunters, by far the most common method of catching pangolins was given as simply picking them up by hand.
While Emogor says the demands of traditional medicine markets are exacerbating the decline of African pangolins – his previous research showed that just shipments intercepted by Nigerian authorities between 2010 and 2021 amounted to 190,407 kilos of pangolin scales taken from around 800,000 dead creatures – pangolins have been exploited in West Africa long before being trafficked to Asia.
The meat is a delicacy in parts of Nigeria, often procured for pregnant women in the belief it helps produce strong babies. Emogor and colleagues surveyed hunters and Cross River locals on “palatability”: asking them to rank the tastiness of almost a hundred different animals eaten in the region, from domestic beef and chicken to catfish, monkeys and antelope.
The three major African pangolin species were rated as the most palatable of all available meats, with average scores of almost nine out of ten, and the giant pangolin considered the topmost appetising meat in the region.
“Pangolins face a lethal combination of threats,” said Emogor. “Pangolins are easy to hunt, breed slowly, taste good to humans, and are falsely believed to have curative properties in traditional medicines. In addition, their forest habitat is being destroyed.”
Emogor’s research led him to set up Pangolino in 2021, a global network of volunteers, scientists and pangolin enthusiasts committed to saving the endangered animal. He points out that the cost of policy interventions to tackle meat-driven pangolin trading might be cheaper than those for an international scales market.
These should include anti-poaching patrols as well as community programmes focused on food security. Through Pangolino, Emogor is piloting interventions in four Southeast Nigerian communities by helping create by-laws that prohibit pangolin killing, with financial rewards for compliance.
“Clearly in designing any intervention we need good information on what’s motivating the hunters,” said Prof Andrew Balmford, co-author from Cambridge’s Department of Zoology. “That’s why studies such as this are vital for effective conservation of endangered species.”
While the latest study focused on Nigeria, researchers say their pangolin hunting and consumption data echo that from countries such as Cameroon and Gabon – suggesting these patterns may be Africa-wide.
Raised on the edge of the Cross River National Park, home to Nigeria’s endangered white-bellied and black-bellied pangolins, Emogor grew up surrounded by wildlife. Yet during childhood he only ever saw dead pangolins, and didn’t encounter a living animal until his mid-twenties.
"If we lose the pangolin, we lose 80 million years of evolution,” said Emogor. “Pangolins are the only mammals with scales, and their ancestors existed when dinosaurs still roamed the planet," added Emogor.
The latest study was conducted by an international team of researchers from the University of Cambridge, Wildlife Conservation Society, Pangolin Protection Network, University of Washington, CIFOR, CARE International, as well as the UK universities of Oxford, Exeter and Kent.
Notes:
*While this is a rough size for some African species, such as the White-bellied pangolin, the Giant Pangolin can grow up to 30kg in weight.
Two pangolin carcasses alongside other animals bound for wild meat markets.
White-bellied pangolins captured in southeastern Nigeria and destined for trade.
Charles Emogor holding a white-bellied pangolin retrieved from a hunter who participated in the study.
Credit
Alex Moore
Aerial view of Cross River National Park.
Charles Emogor with a white-bellied pangolin captured by a hunter who participated in the study.
The agency said the number of people displaced by war, violence and persecution worldwide was 'untenably high' - Copyright Japan's Ministry of Defense/AFP Handout
The number of people forcibly displaced from their homes worldwide has dropped slightly from a record high but remains “untenably high”, the United Nations said Thursday.
A record 123.2 million people worldwide were forcibly displaced from their homes at the end of 2024, said UNHCR, the UN refugee agency.
But that figure dropped to 122.1 million by the end of April this year, as Syrians began returning home after years of turmoil.
Nearly two million Syrians have been able to return home from abroad or from displacement within the war-ravaged country.
But the UNHCR warned that how major conflicts worldwide played out would determine whether the figure would rise once again.
The agency said the number of people displaced by war, violence and persecution worldwide was “untenably high”, particularly in a period when humanitarian funding is evaporating.
“We are living in a time of intense volatility in international relations, with modern warfare creating a fragile, harrowing landscape marked by acute human suffering,” said Filippo Grandi, the UN High Commissioner for Refugees.
“We must redouble our efforts to search for peace and find long-lasting solutions for refugees and others forced to flee their homes.”
– Sudan overtakes Syria –
The main drivers of displacement remain sprawling conflicts like those in Sudan, Myanmar and Ukraine, UNHCR said in its flagship annual Global Trends Report.
Syria’s brutal civil war erupted in 2011 but president Bashar al-Assad was finally overthrown in December 2024.
The report said the first months of this year saw rising numbers of Syrians returning home.
As of mid-May, more than 500,000 Syrians are estimated to have crossed back into the country since the fall of Assad, while an estimated 1.2 million internally displaced people (IDPs) have returned to their areas of origin since the end of November.
UNHCR estimates that up to 1.5 million Syrians from abroad and two million IDPs may return by the end of 2025.
Sudan is now the world’s largest forced displacement situation with 14.3 million refugees and IDPs, overtaking Syria (13.5 million), which is followed by Afghanistan (10.3 million) and Ukraine (8.8 million).
“During the remainder of 2025, much will depend on the dynamics in key situations,” the annual report said.
“This includes whether peace, or at least a cessation in fighting, is possible to achieve, particularly in the Democratic Republic of the Congo, Sudan and Ukraine.”
It also depends on whether conditions for returns improve in Afghanistan and Syria.
Another factor was “how dire the impact of the current funding cuts will be” on responding to displacement and creating conditions for safe and dignified returns.
– One in 67 –
The number of people forced to flee persecution, conflict, violence, human rights violations and events seriously disturbing public order has almost doubled in the last decade.
The figure of 123.2 million worldwide at the end of last year was up seven million compared to the end of 2023.
“One in 67 people globally were forcibly displaced at the end of 2024,” UNHCR said.
In total, 9.8 million forcibly displaced people returned home in 2024, including 1.6 million refugees — the most for more than two decades — and 8.2 million IDPs — the second highest ever.
“We have seen some rays of hope over the last six months,” said Grandi.
But countries such as the DR Congo, Myanmar and South Sudan saw significant new forced displacements as well as returns.
Two-thirds of refugees stay in neighbouring countries.
Iran (3.5 million), Turkey (2.9 million), Colombia (2.8 million), Germany (2.7 million) and Uganda (1.8 million) host the largest refugee populations.
