What the scientists are saying…
Eat nuts to cut dementia risk
Regularly eating a handful of nuts from middle age onwards could help stave off dementia in later life, researchers have found. In a long-term study involving 16,737 people, men and women who started to eat more than two portions of nuts a week in their 40s were 21% less likely to show signs of reduced cognitive function in their 60s, 70s and 80s than people who ate nuts less than once a month. “Higher intake of nuts in midlife was related to a lower risk of cognitive impairment in late life,” said the team, from the National University of Singapore, in the journal Age and Ageing. It’s not the first study to find a link between nut eating and dementia; and a number of studies have shown other benefits associated with nut eating. One found that eating a few nuts a day was associated with a 22% reduced risk of all-cause mortality. However, the researchers behind that study stressed then that they hadn’t established a causal link, and noted that although they had tried to factor in such differences, people who eat nuts regularly may well have more healthy habits overall.
How flies make their getaway
There’s a reason houseflies are so infuriatingly difficult to swat: their legs allow them to fly off five times faster than other types of fly. All fly species have shortened hind wings called halteres, reports the New Scientist. These don’t generate much lift, but are used as sensory organs for balance while the insect is in flight. Now scientists have discovered that the group of flies known as Calyptratae, which includes houseflies and blow flies, rhythmically move these wings when standing. The team also established that this makes their reactions much quicker, though they’re not sure why. Using highspeed cameras to film the flights of more than 20 fly species, the researchers found that, overall, Calyptratae flies were five times faster at taking off than other flies; but when their halteres were removed, they lost this advantage. “It’s part of the reason they’re so successful – they can escape very quickly,” said Assoc. Prof Jessica Fox, a member of the team from Case Western Reserve University in Cleveland, Ohio.
Glass frogs wave to their mates
Glass frogs living in the spray of waterfalls often can’t make themselves heard above the din of the water – so rather than croaking to attract a mate, they wave, and bob their heads. That, at least, is the most likely explanation for the unusual gesturing, which was observed by US researchers working deep in the Ecuadorean rainforest. “One of the best things about fieldwork is that nature is always full of surprises – you never know what discoveries you may happen upon,” said conservation biologist Rebecca Brunner, of the University of California, Berkeley, who spotted the frog’s flipping movements while standing in a pool at the bottom of the waterfall. She said the frog hadn’t kept up the signalling for long, possibly because it uses too much energy. “Presumably visual cues also increase predation risk, although their habitats are incredibly slippery and hard to access,” she added.
Talking is worse than coughing
Talking may lead to more transmission of Covid-19 than coughing, particularly in poorly ventilated areas, researchers from Cambridge University have warned. In the new study, published in the Proceedings of the Royal Society A, a team used mathematical modelling to examine how Covid-19 spreads in different situations indoors. They concluded that when people are together in a poorly ventilated space, and not wearing masks, prolonged talking is more likely to spread the virus than a short cough. The reason is that tiny aerosol droplets linger in the air longer than the larger ones emitted during coughing – which quickly fall to the ground. Whether people actually catch Covid depends on how much aerosol they breathe in, and that will depend on various factors, including whether they are wearing a mask, how close they are to the infected person, and the ventilation in the room. To help people get a sense of the risks of becoming infected indoors, the researchers have developed an online calculator, called Airborne.cam. “The idea is not to obtain absolute risk figures from the tool,” said Dr Pedro Magalhães de Oliveira, “but to use it to see how mitigation strategies impact risk of infection.”