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Defying gravity

Cancer cell clusters are blasting off into outer space, in a research effort that aims to crack one of the final frontiers in cancer biology. Housed in a specially designed biomodule, samples of aggressive ovarian, breast, nose and lung cancer will travel to the International Space Station (ISS). The question at stake: how will the cells behave in microgravity? A malignant tumour consists of cancer cells stuck together that replicate uncontrollably, until a point is reached where the cells begin to break off and invade other parts of the body. This switch between clumping together and spreading isn’t well understood, but researchers reckon the cancer cells have a way to ‘sense’ each other, and that this sense relies on the presence of gravity to function. In a preliminary test in a zero-gravity chamber at the University of Technology Sydney, 80 to 90 per cent of cancer cells were ‘disabled’. Now, the mission to send cancer cells to the ISS aims to replicate this finding—with the hope it could lead to future therapies that trick cancer cells into thinking they’re in outer space. “It would not be a magic bullet, but it could give current treatments like chemotherapy a big enough boost to kill the disease,” said Joshua Chou, the scientist leading the study.
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Strolling to an early grave

New Zealand and United States researchers have found a link between slow walking speed at 45 years old and accelerated ageing. Their research, which used data from the long-running Dunedin Multidisciplinary Health and Development Study, also pegged slow walking to declining brain function, and indicators of reduced brain health in early childhood. The authors recommend that a walking-speed test be introduced in regular doctors’ check-ups, since gait proves to be an inexpensive indicator of general health.
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The fairer sex

Museums have a gender equality problem. Wander the halls of any natural history gallery and chances are, you’ll see more male than female specimens on display. Researchers at London's Natural History Museum analysed 2.5 million records from five prominent museums around the world and found that just 40 per cent of bird specimens are female, while 48 per cent of mammal specimens are female. This slight percentage difference equates to 40,000 more male mammals housed in museums. It’s not just an issue for the stuffed display animals, either—the male bent also afflicts research collections. When it comes to type specimens—the ‘official’ specimen used to scientifically describe a species—the sex ratio drops further, with just 27 per cent of birds and 39 per cent of mammals being female. These ratios have remained unchanged for the last 130 years, except in species with marked sexual dimorphism. This is where males have ostentatious features such as bright colours while females may be more understated in appearance. In such species, the proportion of females in museum collections has decreased. This bias towards males has implications for our understanding of evolution, genetics and ecology. “Natural history collections play a critical role in … answering vital questions for the future of biodiversity,” the study authors wrote. “These results imply that previous studies may be impacted by undetected male bias, and vigilance is required when using specimen data, collecting new specimens and designating types.”
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More than you can chew

The toutouwai (North Island robin, Petroica longipes) has eyes bigger than its stomach. Weighing about the same as a lightbulb, toutouwai regularly take down large invertebrates including wētā, stick insects and even 30-centimetre-long earthworms. But there’s only so much the tiny toutouwai can devour of these meals. Rather than let that protein go to waste, toutouwai are adept at storing leftovers—a caching behaviour similar to a squirrel hiding nuts for winter. To remember where all these tidbits are stored, toutouwai need a good memory map. Researchers gave 63 wild birds a puzzle with a mealworm treat hidden in one of eight compartments. The puzzle was placed in the toutouwai’s territory several times per day, with the treat always hidden in the same compartment. Toutouwai learned the location of the snack, opening fewer compartments to find the mealworm over time. Following these individuals over the next breeding season, researchers found that males with better memory raised more chicks and fed their offspring larger prey items. But for females, food memory was not linked to reproductive fitness, leading the researchers to speculate that females may have other traits under selection pressure—perhaps related to nest-building.
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Why 10,000 steps?

Did you ever get a new Fitbit? Did you then spend the next few weeks compulsively checking your wrist, seeing how ‘good’ you’d been that day? Did you take the dog for an extra walk at 10pm just to watch the device tick over 10,000 steps, and go to bed basking in the glow of your achievement because Fitbit, and science, told you that was the minimum distance humans should walk each day to be healthy and live longer? Then welcome. Come on in. Join the club of those of us who’ve been royally duped by health and wellness marketing. Trouble is, there’s little evidence attached to 10,000 steps being better than any other distance to walk in a day. A study of 16741 women in the United States, with an average age of 72, found that after 7500 steps per day, the benefits appeared to level out, at least in the women studied. Investigators from Brigham and Women’s Hospital in Boston found that regardless of intensity, those who walked about 4400 steps each day lived longer than those who averaged just 2700 a day, but that this drop in mortality rates plateaued at 7500. Meanwhile, an Australian study of 1697 people aged 55-85 found that benefits generally increased per extra 1000 steps gained. So how did 10,000 steps become popular? It may stem from a Japanese pedometer company in the 1960s which felt that the character for 10,000, 万, looked similar to a running figure. Scientists are now looking at the speed of steps, or cadence, as an indicator of health, rather than distance.
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March of the penguins

Climate change could spell the end for emperor penguins by the year 2100—that’s the somber prediction of a new international study. If current warming trends continue, emperor penguins will be marching toward an 86 per cent population decline by the end of the century, at which point, “it is very unlikely for them to bounce back,” says study author Stephanie Jenouvrier, a seabird ecologist from Woods Hole Oceanographic Institution. Emperor penguins, the largest penguin species on Earth, require sea ice of a specific type to survive. It must be fixed to Antarctica’s shoreline, but also extend far enough into the open sea to allow for foraging. Without sea ice, emperor penguins are unable to raise their chicks and numbers plummet. By combining two computer models, researchers mapped future sea ice distribution and modelled how the penguin population would respond to changing ice conditions under three different climate scenarios. If humans limit warming to 1.5ºC, as proposed in the Paris Agreement, sea ice will only decrease by five per cent, leading to a 19 per cent drop in emperor penguin numbers by 2100. Under a 2ºC warming regime, sea ice loss triples and 31 per cent of the population is lost. The worst case—guaranteed extinction—arises if no action is taken and current warming is allowed to continue unabated. “If we don’t hit the Paris Accord emissions goals,” says Michelle La Rue, study co-author from the University of Canterbury, “emperor penguins are in deep trouble.”
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Rise of the lake slime

By studying 71 lakes in 33 countries from space, researchers from Stanford University have found that toxic algal blooms in freshwater have been increasing since the 1980s. Using satellite data from the past 30 years, they found blooms were becoming more frequent in 70 per cent of the lakes studied, but that this wasn’t linked to usual causes, such as fertiliser use or rainfall changes. The lakes that had fewer blooms over time, however, had warmed less than other lakes.
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Reef doctors

After severe coral bleaching—the stress response of coral to higher sea surface temperatures—parrotfish thrive, a new study by the Australian Institute of Marine Science (AIMS) has found. Researchers looked at fish populations on two bleached reef areas—the Great Barrier Reef and the Chagos Archipelago in the Indian Ocean, 8000 kilometres away. Parrotfish populations in damaged reef areas were two to eight times as high as normal, and individual fish about 20 per cent larger. The fish use their beak-like teeth to scrape microorganisms off coral. Study co-author Brett Taylor believes the parrotfish’s presence helps the coral repair process, as their feeding creates large areas of newly barren surfaces. He thinks coral and parrotfish might create a positive feedback loop: the fish nibble away microalgae and cyanobacteria ‘scunge’ from the coral, giving it a better chance to recover. “Parrotfish are a vital link in the reef ecosystem,” says co-author Mark Meekan. “As herbivores, their grazing shapes the structure of reefs through effects on coral growth and suppression of algae that would otherwise proliferate. Because of these important ecological roles, they have been described as ‘ecosystem engineers’ of reef systems.”
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Global shapers

When did the Anthropocene, the current geological epoch, actually begin? In research published in Science in August 2019, Australian social scientists say humans have been the main influence on the Earth’s climate and environment since 2000 BCE. “The activities of farmers, pastoralists and hunter-gatherers had significantly changed the planet four millennia ago,” writes co-author Andrea Kay from the University of Queensland. “The long-term cumulative changes that early food producers wrought on Earth are greater than many people realise.”
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Penguin of the north

On Scotland’s remote St Kilda island in the summer of 1840, a group of fishermen found a strange seabird sleeping on a ledge. It was black-and-white, flightless, and enormous. The men took it home to their village and tied it up in a stone hut. For three days the bird complained and tried to bite anyone that came near. Then a wild storm arose. Fearful the bird was a witch, and had sent the tempest to punish them for capturing it, the superstitious villagers stoned it to death. It took an hour to die. In reality, the witch-bird was a great auk—the last one ever documented in the British Isles. Four years later, the last pair in existence was killed in Iceland by hunters looking for museum specimens. The species—sometimes known as the penguin of the north—had ranged across the North Atlantic in the millions. What happened? Was the species in decline before intensive harvesting started in the 1500s—or was human hunting alone enough to drive such a numerous species into oblivion? To find out, genetic researcher Jessica Thomas from the University of Swansea analysed the mitochondrial DNA of 41 long-dead great auks. The data showed the species had enjoyed high genetic diversity and a constant population size for thousands of years, and that great auks from across the North Atlantic were able to meet and breed. The researchers then simulated how much hunting would have been necessary to drive the great auk to extinction within 350 years, and found that an annual harvest of 210,000 birds and fewer than 26,000 eggs would have inevitably led to extinction. Sailors’ journals and other historic reports suggest the actual number of birds killed for their meat, eggs, and feathers is likely to have been far higher. Then the museum trade finished them off. “There are lot of very gruesome sailors’ records in terms of how they used to kill them,” says Thomas. “They would have these huge pits where they would corral the great auks into stone huts and then burn them with the oil from their dead relatives.” The study highlights that “pretty much anything is susceptible to extinction”, says study co-author Michael Knapp from the University of Otago, where Thomas was based for some of her research. “People went to the North Atlantic and it was full of great auks. Nobody would have thought there was any risk.” Some of the great auk’s relatives—the puffin, the murre—are still hunted today, and should be more closely monitored, says Knapp. “Anything we exploit in large numbers we need to be very careful about, even if we think there’s a lot of them.”
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Finding faults

Just after midnight on November 14, 2016, more than 24 fault lines around Kaikōura ruptured in spectacular fashion. One of these rifts—the previously unmapped Papatea Fault—threw up a few extra surprises for scientists. Normally, the rupture of a fault is caused by a build-up of stress. But Papatea was stress-free until its rupturing neighbours squeezed it, triggering a violent fracture. In a matter of seconds, the earth split open along 19 kilometres and sections of mountainous land were shifted upwards by eight metres. Of the 24 fault lines, Papatea produced the largest vertical movement. At first, Papatea’s behaviour confused scientists, because the fault wasn’t under strain. In a study published in Science Advances in October, New Zealand and Canadian researchers used before-and-after images of the fault line to create a model and figure out what happened. It’s another unusual aspect of the most complex earthquake ever studied, with implications for assessing seismic risk. Current earthquake forecasting is based on the strain model, where faults accumulate tension until they fail, but Papatea shows that displacement is also a risk, says Mark Stirling, chair of earthquake science at the University of Otago: “A ten-metre displacement in a built-up area or beneath a critical facility, such as a large dam, would have significant consequences.”
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Machine medicine is catching up

Artificial intelligence can spot diseases with about the same accuracy as human professionals, according to a systematic review and meta-analysis published in The Lancet Digital Health in September. Across 14 studies, ‘deep learning’ algorithms correctly detected conditions ranging from cancers to eye diseases in 87 per cent of cases, compared to 86 per cent by doctors. Artificial intelligence was also marginally better at identifying patients who had a clean bill of health.  
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Have you tried stripes?

Painting cows with black and white stripes reduces fly bites by 50 per cent, according to a study by a team of scientists in Japan, published in PLOS One in October. The zebra-print cows displayed fewer signs of annoyance, such as tail flicking and head shaking, and attracted lower numbers of biting flies than unpainted cows. The study was inspired by previous research suggesting the zebra’s iconic striped coat functions as a fly deterrent. The stripes are thought to work by confusing the insects: the pattern interferes with flies’ motion detection, and they fail to land on the striped surface. (This is, however, just one of a number of theories attempting to explain the evolutionary advantage of the zebra’s stripes.) Biting flies are a significant pest for cattle worldwide, including in New Zealand. Their persistent attacks cause stress and prevent cattle from sleeping and eating—which in turn affects growth and milk production.
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Quite shocking

Genetic reanalysis in the Amazon has revealed that the electric eel is, in fact, three different species, including one—Electrophorus voltai—that can deliver an 860-volt shock. (That won’t kill a healthy person, says ichthyologist and lead author Carlos David de Santana, from the Smithsonian National Museum of Natural History.) The new species is now officially the strongest bioelectricity generator known, making the previous record of 650 volts a mild tingle.
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Gender reveal

Embryonic turtles can choose what they’ll be when they grow up: male or female. In particular turtle species, the temperature of the egg appears to determine the sex of the hatchling. Research published in August in Current Biology found that embryos are able to move around within the egg to find different temperatures. Wei-Guo Du and colleagues at the Chinese Academy of Sciences incubated turtle eggs at a range of temperatures, finding that an embryo could experience a gradient of up to 4.7°C within its egg. (A temperature change larger than 2°C can alter the sex ratio of many turtle species.) In half the eggs, researchers applied a chemical that blocked the embryos’ temperature sensors. When the eggs hatched, the embryos that weren’t able to sense temperature were either almost all males or almost all females. But the temperature-sensing embryos developed about half and half males and females. “The most exciting thing is that a tiny embryo can influence its own sex by moving within the egg,” says Du. This indicates that turtles may have the ability to shield themselves against extreme thermal conditions. Du warns that this may not be enough to protect them from rapid climate change, which is predicted to create female-biased populations. “However, the discovery of this surprising level of control in such a tiny organism suggests that in at least some cases, evolution has conferred an ability to deal with such challenges.”
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Our newest weapon is a sponge

A sea sponge may one day save millions of lives, according to a study published in Scientific Reports in October. Tuberculosis kills 1.8 million people each year, more than any other disease, and current vaccines are struggling to contain it. That’s because Mycobacterium tuberculosis, the organism that causes TB in humans, is quick to mutate, meaning it can soon evolve drug resistance. The quest for a better vaccine has led scientists beneath the waves, looking for bioactive molecules in sponges: compounds that might one day comprise the basis of new vaccines. Over three years, the Centenary Institute and the University of Sydney analysed around 1500 sponges, and discovered that a species of Tedania, a genus found around Australia and New Zealand, possesses potent powers against M. tuberculosis. The active component, Bengamide B, was able to halt drug-resistant TB strains, and did not harm human cells. “Bengamide B shows significant potential as a new class of compound for the treatment of tuberculosis,” said the study’s lead author, Diana Quan, “and also importantly, for the treatment of drug-resistant TB.”
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Galactic snack

Our next-door neighbour is a cannibal. Andromeda, the closest spiral galaxy to the Milky Way, has a history of eating smaller galaxies, and we’re next on the menu—in about four billion years. Research published in Nature in October documents the leftovers of galactic meals: dense star clusters called globular clusters dotted throughout the stellar halo orbiting Andromeda. By tracing the faint remains of smaller galaxies embedded in the globular clusters on Andromeda’s outskirts, researchers reconstructed how and when the smaller star systems were gobbled up. “We are cosmic archaeologists, except we are digging through the fossils of long-dead galaxies rather than human history,” said the study’s co-author, Geraint Lewis from the University of Sydney. Andromeda is on a collision course with the Milky Way—so now we have a clearer picture of the ultimate fate of our galaxy.
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The case of the missing sharks

Normally, more than 200 sightings of great white sharks are recorded every year in False Bay, near Cape Town, South Africa. This year, that number is zero. Receivers that are supposed to ‘ping’ when a tagged shark passes by remain silent, while whale carcasses usually found in the bay are free of shark bite marks. False Bay is a renowned great white hotspot, and shark scientists are puzzled by the predators’ absence. It’s possible that orcas are the culprits—they’re known to attack great whites, and have a particular taste for their livers. Indeed, sightings of great whites decreased after two orcas visited False Bay in 2015. Alleged victims of orca predation have washed up along the South African coast, their livers removed with surgical precision—the orca’s calling card. This is also consistent with observations from Australia and California, where orcas on the prowl have led to a mass exodus of great whites. But there’s another suspect in this case: humans. It’s possible that changing prey distribution, pollution or overfishing could also be responsible for the missing sharks.
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Thin-skinned pāua

Warming seas will make life much harder for pāua, a NIWA study has found. Scientists raised young pāua in seawater of various temperatures and pH levels, then monitored their growth. “Essentially, seawater of the future will be warmer, with lower pH levels,” said Vonda Cummings, pictured, who led the study. “We found that the outer layer of pāua shells gets etched by seawater with lower pH, especially if the water was warmer.” The pāua were sensitive to temperature variations as small as 2ºC, “and that will affect the thickness of pāua shells, which could mean they are not as resistant to waves and predators”.

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