Sommaire pour November 2020 de BBC Science Focus Magazine

In response to the question ‘Is it possible to recycle plastics an infinite number of times?’ (Summer, p85) you wrote that glass and aluminium don’t degrade during recycling. This is not the case with glass. If you took all the bottles made in a container factory and kept feeding them back into the furnace, the glass would gradually become more and more viscous, and eventually the machines would be unable to produce any more bottles. I once was faced with the problem of running out of glass in a tank furnace, which was never emptied but topped up with ‘batch’ (raw materials) weekly. As we kept gathering the glass it became more difficult to work with and the quality worsened. The resulting products then cracked during cooling because the glass…

Meet Magawa, the first rat to ever be awarded a PDSA gold medal. The five-year-old African giant pouched rat has found 39 landmines and 28 other potentially dangerous items of unexploded ordnance over the past four years, sniffing his way across 140,000 square metres of land – the equivalent of 20 football pitches. He was born in Tanzania in November 2014 and completed nine months’ of training at APOPO’s HeroRAT Training and Research Center in Tanzania, where he learned how to detect the smell of explosives using his nose. He was then sent off to Siem Reap in Cambodia to get to work sniffing out landmines. “APOPO’s HeroRATs significantly speed up landmine detection, using their amazing sense of smell and excellent memory. We use clicker training to teach rats like…

A new hearing aid that costs less than £1 to make has been developed by researchers at the Georgia Institute of Technology. Even in the UK, around 11 million people are living with hearing loss, of whom 8 million are aged 60 or older. A hearing aid can help those who still have some hearing ability left, but are finding it hard to hear specific pitches of noise – such as doorbells or phones ringing – or struggle to pick out individual voices in a conversation. Hearing aids help because they can be tuned to boost sounds at certain frequencies, depending on the type of hearing loss a person has. For example, older adults tend to lose the ability to hear sounds at higher frequencies. “I was born with hearing…

Nearly 40,000 people from around the world have taken part in a study to reveal global responses to touch. Results show that attitudes are nuanced, though age and personality had a strong influence on a person’s inclination, or aversion, to physical contact. In the midst of the coronavirus pandemic, being touched by a stranger is a frightening thought. Those who are self-isolating have limited or even no physical interactions, while doctors and nurses on the frontline feel the pulses of their patients only through layers of PPE. But for a surprising amount of people, being deprived of touch is not a new feeling. Over half of respondents to The Touch Test, which ran from 21 January to 30 March 2020, said they got ‘too little touch’ in their day-to-day life.…

Viruses replicate during the infection process. For most viruses, replication results in many errors, which means that viruses like the flu mutate rapidly. This can lead to treatments and vaccines becoming ineffective, and is one of the reasons why we need a new flu jab every year. Coronaviruses will accumulate mutations, but they do so at a slower rate because they ‘proofread’ their replicated genome. Mutations do occur, though, and could have many different effects on the SARS-CoV-2 coronavirus and our ability to control the pandemic. The majority of mutations will have no impact on the virus or on the disease. Occasionally a mutation will enable greater growth or transmissibility, or will escape from the immune system (meaning the immune system no longer responds to it), in which case the…

Smart speakers are to speakers what smartphones are to phones; a technology that turns a utilitarian device into something that can do so much more. After a slow start, smart speakers are becoming increasingly popular, with almost 3 out of 10 Brits now owning one. With a smart speaker, things you to have to dig out your phone for, or hop on a computer to accomplish, can be done hands-free just by speaking a few words. Look up the opening hours for a museum while you’re packing lunch, set a timer for your boiled egg, add more eggs to your shopping list, all with just a few words. Some smart speakers also have screens attached, to give you visual feedback (such as showing you which song is playing) as well…

SOLAR-POWERED SEA SLUG It looks like a tiny, cartoon sheep, but this is in fact one of more than 4,700 known species of sea slug that creep and occasionally swim through the ocean. Known as the leaf sheep (Costasiella kuroshimae), this sea slug lives around coral reefs, where it grazes on clumps of algae. The green colouration comes directly from its food – a leaf sheep retains the algae’s chloroplasts (tiny cellular structures that harness the Sun’s energy to make sugars), and incorporates them into its skin, where they continue to photosynthesise. This trick of stealing chloroplasts, called ‘kleptoplasty’, stops the leaf sheep from starving when there’s no food around. It’s one of a range of weird and unique survival techniques that sea slugs have evolved. The term ‘sea slug’…

It’s that age-old dilemma. Where to keep all those moulted heads that you’ve grown out of? On the mantelpiece? In the wardrobe? Or on top of your head, like the world’s most outrageous fascinator? If you’re a caterpillar of the Uraba lugens moth, you’ll no doubt plump for the latter. Nicknamed ‘the mad hatterpillar’, after the Mad Hatter from Lewis Carroll’s Alice’s Adventures in Wonderland, this caterpillar lives in New Zealand and Australia, where it is a serious pest of eucalyptus trees. It munches eucalyptus leaves down to the veins - a talent which has also earned it the name of ‘gum-leaf skeletoniser’ (eucalyptus trees are commonly known as gum trees). Just like all caterpillars, U. lugens must regularly shed its exoskeleton in order to grow. But unlike other larvae,…

Neanderthal DNA may increase severity of COVID-19 Genes from our ancient cousins seem to be linked to a serious response to the coronavirus p26 Touching issue Prior to the pandemic, more than half of us wanted more physical contact p31 The European Space Agency (ESA) has announced a multi-billion-euro investment to the robotic and human exploration of the Solar System. It represents a large expansion to the contribution that Europe is already making to Artemis, the NASA programme to land the first woman and the next man on the Moon during 2024. The new contracts are worth a total of €2.9bn (£2.6bn approx) and are designed to help Artemis become a long-term sustainable exploration of the Moon by astronauts, and take Mars exploration to the next level by returning Martian…

The megalodon made famous by the film The Meg was abnormally large compared to its relatives, a new study has found. Megalodon stalked the world’s oceans between 20 and 3.5 million years ago. It was around 15 metres in length - over three times longer than the average great white shark - and was probably one of the largest and most powerful predators ever to have lived. The ancient behemoth belongs to a diverse group of sharks called the lamniforms, which also includes the great white. Calculating the size of extinct lamniforms is often hampered by a lack of fossils, and most are estimated from the size of their teeth (tooth fossils are the most common because sharks continually shed their teeth, going through up to 40,000 in their lifetime).…

“Nobody ever checked whether you’re actually using it as intended, you’re merely getting a car with several thousand pounds off the cost” Plug-in hybrid electric vehicles (PHEVs) are supposed to be the perfect compromise between practicality and carbon emissions, with an electric motor to handle your commute and an engine for range. But they might not be as eco-friendly as they appear. A new report from the campaign group Transport and Environment (T&E) has shown that PHEVs emit, on average, over 2.5 times more CO2 than their official test values. The group recommends that the UK government commits to the ‘earliest feasible phase-out date’ for all cars with engines: internal combustion engine (ICE) cars, conventional hybrids and PHEVs. HOW MUCH CO2 DO PHEVs EMIT? Laboratory tests for PHEVs found that…

KAMILA MAGOMEDOVA (AGED 13) DO WET SHEEP SHRINK? Wool fibres aren’t completely smooth - they have microscopic scales that interlock with those on adjacent fibres when you wash them, pulling them together like a ratchet and causing them to contract. That’s why your woolly jumper shrinks in the wash. Luckily, sheep secrete an oily substance from their skin called lanolin, which lubricates the wool and prevents the fibres from tangling when they get wet, so their fleece stays nice and full in the rain. When woolly jumpers shrink, they don’t stretch again when they dry out. So a shrunken sheep would be shrunken forever! LV WINNER Kamila wins a Turing Tumble, worth £56. Turing Tumble is a new game where players build mechanical marble-powered computers, to solve logic puzzles. It’s…

WHY IS THERE A HURRICANE SEASON? WHAT CAUSES HURRICANES? Hurricanes are some of the most powerful storms on Earth, drawing their energy from warm tropical waters in the Atlantic or northeastern Pacific. In other parts of the world, these swirling storms are known as typhoons (in the northwestern Pacific) or cyclones (South Pacific and Indian Ocean). These storms form above ocean waters when warm, moist air rises. This draws in more humid air from surrounding areas, and as the air rushes in, the Coriolis effect (created by the Earth’s spin) causes it to follow a curved path, leading the developing storm to spin anticlockwise in the northern hemisphere. As the rising air cools, the moisture condenses out and forms rain clouds. As long as thereʼs sufficient heat from the oceans,…

ACROSS 7 Stone designs are captivating doctor (5) 9 Sing about oil mixed with medium metal (7) 10 Also free to acquire old robot (7) 11 Trace of wheat, say (5) 12 Scottish team, or maybe Cornish (6) 13 Sponsor has right to devotion (6) 16 Mean to study broken toe (6) 17 Pass law around start of year (6) 19 Small amount of money for seafood (5) 21 Note a great deal – it’s different around the vocal cords (7) 22 Warning device for hog moving north (7) 23 Shy and stupid to object to return (5) DOWN 1 What’s left, on the day, is fair (8) 2 Trains so curiously to be a criminal (8) 3 Cold skin gets rebuke (5) 4 Bullet for a garden pest (4)…

The popularity of many flat-faced dog breeds such as French bulldogs has risen dramatically in recent years, despite regular assertions that they are prone to many health issues including breathing problems and sore eyes. However, there has been limited reliable evidence on the wider general health of flat-faced – or brachycephalic – dogs across the spread of common disorders, when compared to other dog breeds. Now, a study led by the Royal Veterinary College’s VetCompass programme, which examined the overall health of a random sample of 4,169 flat-faced dogs compared to 18,079 other dogs that attended veterinary practices in the UK, has confirmed that brachycephalic dogs are more likely to suffer from a range of health disorders. Out of the 30 common disorders found across both groups, flat-faced dogs have…

With plans underway to revisit the lunar surface and eventually send a crewed mission to the Red Planet, future space exploration missions are likely to involve an extended stay. Any brave souls wishing to take on such an endeavour will need a reliable building material to construct tools and shelters. Chitin, an organic polymer found in the cell walls of fungi and the exoskeletons of crustaceans and insects, could potentially be used as a building material by human settlers on Mars, according to a team led by Dr Javier Fernandez at Singapore University of Technology and Design. Early explorers are likely to consume insects as a source of protein, so chitin would be in ready supply. The team first created chitosan, which is made by treating chitin with an alkaline…

Alexander Fleming famously discovered penicillin in one of science’s greatest good luck stories in 1928 while working at St Mary’s Hospital Medical School. The drug was produced by a mould in the genus Penicillium that accidentally started growing in a Petri dish he was using to study the bacteria Staphylococcus aureus. Much to his surprise, he noticed that the mould was suppressing the growth of the bacteria and so the first antibiotic was discovered. Now, researchers from Imperial College London, the Centre for Agriculture and Bioscience International (CABI) and the University of Oxford have sequenced the genome of Fleming’s original Penicillium strain by re-growing it from a frozen sample kept at the culture collection at CABI. “We originally set out to use Alexander Fleming’s fungus for some different experiments, but…

Sometimes, less really is more: the evolutionary loss of a finger may have helped a group of parrot-like dinosaurs to thrive more than 68 million years ago. Multiple complete skeletons of a new species of oviraptor - feathered, omnivorous creatures sporting large, toothless beaks similar to the type seen in species of parrot today – were unearthed in the Gobi Desert in Mongolia and subsequently studied by researchers from the University of Edinburgh. Dubbed Oksoko avarsan, the newly discovered dinosaurs were found to have just two fingers on each forelimb – one less than other members of the oviraptor family. This is the first time that digit loss has been observed in the three-fingered family of oviraptors and may suggest adaptability that enabled the animals to spread during the Late…

As many as 1 in every 10 COVID-19 patients could end up with symptoms lasting for longer than three months, with sufferers around the world terming this ‘long COVID’. Researchers believe that these symptoms are the ‘after-effects’ of the virus, due to damage caused to the organs, immune and nervous systems. People who have been ill enough with COVID-19 to be hospitalised are more likely to need an extended recovery time than those who weren’t as badly affected, but it seems long COVID can strike anyone, of all ages and backgrounds. We already know that there are viruses that can cause symptoms for weeks, months or years postinfection. Some long-term illnesses, such as myalgic encephalomyelitis (ME) and chronic fatigue syndrome, are thought to be post-viral, so it would make sense…

SONOS ONE PRICE: £179.99 ASSISTANT: ALEXA, GOOGLE ASSISTANT COLOURS: BLACK, WHITE SPEAKERS: TWO CLASS-D DIGITAL AMPLIFIERS, ONE TWEETER, ONE MID-WOOFER SIZE: 161.45 X 119.7 X 119.7MM, 1.85KG OUR CHOICE This little speaker packs a lot of punch. It has two voice assistants, and hooks into Sonos’s wider world of wireless music, making it the most versatile speaker we tested. It also works with Apple’s AirPlay system (letting you play music directly from your iPhone). The Sonos One works incredibly well as a smart voice assistant, especially considering it’s not made by Amazon or Google. This is a big reason why it’s our top choice; you’re not locked in to one ecosystem as you are with most other smart speakers, you can switch between Alexa and Google at will. If you’re…

When the UK government decided to cancel school exams due to the coronavirus pandemic, they gave examination regulators Ofqual a challenge: allocate grades to students anyway, and make sure the grades given out this year are equivalent in standard to previous years. Ofqual’s solution was to create an algorithm – a computer program designed to predict what grades the students would have received if they had taken exams. Unfortunately, when the computer-generated grades were issued, 40 per cent of A-Level students got lower grades than their teachers had predicted. Some of them several grades lower. Promised university places were withdrawn. Lawyers offered to take legal action against Ofqual. Angry teenagers took to the streets with placards saying ‘F**k the algorithm’. Worse, students at large state schools seemed to have lost…

HOW CAN I SEE THE PLEIADES STAR CLUSTER? WHEN: OCTOBER TO APRIL The Pleiades, or Seven Sisters, is the most well-known star cluster in the night sky. It’s what’s known as an ‘open cluster’, which is a group of stars that form from the same huge cloud of dust and gas. As the cloud collapses under gravity, temperatures rise and stars begin to take shape, becoming loosely bound by their mutual gravitational attraction. The Pleiades contains some 3,000 stars, all less than 100 million years old, making them mere babies compared to our Sun’s 4.6 billion years. The cluster’s name possibly comes from the Ancient Greek word plein, meaning ‘to sail’, because the first appearance of the cluster in the dawn sky each year heralded the start of the sailing…

STAYING WARM IS A BALANCE… … between heat produced and heat lost. When we get cold, we often shiver because shivering generates heat. At the same time, blood flow is diverted away from the extremities, like the fingers and toes, to the torso. This helps protect vital organs, like the heart and lungs, and reduce heat loss to the surroundings. SOME PEOPLE FEEL THE COLD MORE THAN OTHERS… … even in the same environment. This is to do with size, fat and metabolism. Smaller people with less body fat lose more heat to their surroundings than bigger people with more fat. Bigger people may have more muscle mass, and are therefore able to produce more heat. LAYERING IS CRITICAL. It acts as insulation because it traps warm air close to…