BBC Science Focus Magazine的August 2021目录

The Amazon rainforest is now emitting more carbon than it is able to absorb, a study by a team of international researchers has found. For generations, the vast area of forest, often referred to as the ‘lungs of the Earth’, naturally absorbed carbon dioxide in the air. But now, the researchers say it is putting out around one billion tonnes of carbon dioxide more a year than it can absorb. The whole Amazon basin comprises about half of the planet’s tropical rainforests, though the study only covered the forests found in Brazil, which make up about 60 per cent of that figure. The emissions are largely driven by fires set by developers deliberately burning down the trees to clear agricultural land for the grazing of cattle or the growing of…

Pterosaurs, a group of flying reptiles that zipped around the Earth 228 to 66 million years ago, may have been able to fly as soon as they hatched, research from the University of Portsmouth has found. A team of scientists studied four previously unearthed hatchling and embryo fossils from two pterosaur species, Pterodaustro guinazui and Sinopterus dongi. They compared wing measurements, along with the size and strength of the humerus bone, with those of adult pterosaurs of the same species. “These tiny animals – with 25cm wingspans and bodies that could neatly fit in your hand – were very strong, capable fliers,” said study co-author Dr Mark Witton. “Their bones were strong enough to sustain flapping and take-off, and their wings were ideally shaped for powered, as opposed to gliding,…

“Each additional step, roll, or shuffle, particularly into a new environment, may make you feel less like your memory is slipping away during socially distanced periods” From ‘poor’ to ‘excellent’, how do you rate your memory before you began social distancing? And how do you rate your memory today? These are two of the questions PhD student Natan Feter and colleagues, from the Universidade Federal de Pelotas in Brazil, posed in their recent study examining the relationship between memory and social distancing measures. It’s a question that’s been on many people’s minds lately: how has lockdown affected our memories? Feter’s team found that roughly one-third of adults from southern Brazil reported worse memory since the beginning of social distancing restrictions. Given that Brazil has never had a national lockdown, and…

EGG EMOJI “What looks like a mouth is actually a fracture-line that runs along the top of the egg,” says shield bug expert Maria Justamond, commenting on this cluster of emoji-like insect eggs on the underside of a leaf. “When the baby shield bug is ready to emerge, the egg opens up like a trapdoor.” More than 99 per cent of all animals that have ever lived on planet Earth have, in the first moments of life, hatched from an egg. Yet for all their abundance, eggs continue to amaze scientists with their unique adaptations and mind-blowing evolutionary workarounds. “I’ve always had a bit of a soft spot for their eggs,” Justamond adds. “I love how varied they are in colour and size, and how each shield bug species has…

TELL US ABOUT THE SAMPLE RETURN MISSION. The Mars Sample Return mission is the first mission – programme actually, because more than one craft is required – to return samples from another planet. We have samples from the Moon returned by the Apollo missions, by the Russian rover and most recently by the Chinese. And we’ve returned samples from asteroids [via missions run] by the US and Japan. But we’ve yet to return a sample from Mars. That’s the objective. The first step is the Perseverance rover, which is beginning to collect samples after NASA landed it successfully on Mars in February this year. The Mars Sample Return programme is a joint endeavour between NASA and the European Space Agency (ESA), although NASA is leading it. NASA will be responsible…

Every week on BBC World Service, CrowdScience answers listeners’ questions on life, Earth and the Universe. Tune in every Friday evening on BBC World Service, or catch up online at bbcworldservice.com/crowdscience IS MY NEIGHBOUR’S NOISE HARMING MY HEALTH? We’ve all felt annoyed by noises that are outside of our control, whether it be a car horn, construction work, or an inconsiderate neighbour’s music. Regular exposure to sounds below 80 decibels (dB) won’t physically harm our ears, but even quiet sounds can have long-term effects on our brains and bodies. Road traffic and aircraft noise have been linked to impaired concentration, learning and memory, plus increased risk of cardiovascular disease. For example, one analysis found that for every 10dB increase in traffic noise, a person’s risk of coronary heart disease rose…

HOW CAN I SEE JUPITER AT OPPOSITION? WHEN: 19 AUGUST August is quite often one of the quieter months in the astronomical calendar. With the Sun setting later through the summer months, it can make fainter objects challenging to observe. The plus side is that warm weather makes it the perfect time for beginners to get to know the night sky without winter coats and woolly hats, however. A particular gem is the king of the Solar System: Jupiter, which comes into opposition on 19 August. As the outer planets orbit around the Sun, Earth occasionally finds itself between the Sun and another planet, with all three in direct alignment. When this happens, we describe it as a planet being in opposition. Oppositions occur roughly annually (with Mars being the…

ACROSS 1 Space for a victory in an urban area (6) 4 He gets up part of stairs (5) 8 Intended to have miserly time (5) 9 Costume remaining the same (7) 10 Like a writer, no evergreen (5) 12 Arranged loan with zero return – just a bit of wool (7) 13 Returned to list previous works (4,9) 15 Mary rewrote a book on an insect (4,3) 17 Get rid of a channel (5) 19 Title of the French king overturning fashion (7) 20 Characteristic art, transforming object (5) 22 Returning, say, taking road for some distance (5) 23 Look for son and reach out (6) DOWN 1 Mark finds a butterfly (5) 2 By way of answer, six went first (3) 3 Huge bird I can broadcast (7)…

Human Error This new podcast, presented by comedian Olga Koch and journalist Hussein Kesvani, explores the biggest most interesting and surprising tech stories of 2021. BBC Sounds, available now The Life Scientific Jim Al-Khalili’s fantastic radio programme returns in September. He’ll be joined by a range of expert guests, including neuroscientist David Eagleman, mathematician Hannah Fry and psychologist Alice Gregory. BBC Radio 4, starts 7 September Our Lives Returning for a fourth series, Our Lives shares the stories of 12 ordinary people doing extraordinary things around the UK. BBC One, 11 August, check Radio Times for details…

For the first time, astronomers have detected a dusty ring around an exoplanet where moons could be born. They hope the discovery will teach us more about how both planets and moons are formed. The newly forming exoplanet PDS 70c orbits a star almost 400 light-years from Earth, along with protoplanet PDS 70b. PDS 70c was discovered with the European Southern Observatory’s Very Large Telescope in 2019. Previous studies found hints that it may have a moon-forming disc around it, but astronomers have now confirmed it, thanks to new, high-resolution images from the Atacama Large Millimetre/ submillimeter Array (ALMA). “Our work presents a clear detection of a disc in which satellites could be forming,” said Dr Myriam Benisty, at the University of Grenoble, France and the University of Chile. “Our…

Tooth loss is linked to cognitive decline and dementia, a study at NYU Rory Meyers College of Nursing has found. However, the researchers did not see the same effect in older adults with dentures. The team analysed 14 studies on the link between tooth loss and cognitive function, involving a total of over 34,000 adults. They found that tooth loss was linked to a 1.48 times higher risk of cognitive decline, and a 1.28 times higher risk of dementia, even after they controlled for other factors. However, those who had dentures did not have the same risk. In fact, the researchers found no significant link between tooth loss and cognitive decline in people with dentures. People with missing teeth were more likely to be cognitively impaired if they didn’t have…

The gene-editing tool CRISPR has been used to modify the genes of everything from squid to tomatoes. Now we can add marsupials to the ever-expanding list, as a team at RIKEN Center for Biosystems Dynamics Research in Japan have used it to tweak the genes of a South American species of opossum to change its colour. Most of the previous research in the field has focused on switching off the genes of mice and rats in order to determine their function. However, as marsupials have a number of unusual genetic quirks compared to other mammals, they present biologists with a unique opportunity to study everything from reproduction and foetal development to immunology and cancer. The opossum, which is thought to be the ancestor of all marsupials, was chosen as it…

SCIENCE BEHIND THE HEADLINES Larks vs owls | Beaver culls | Lockdown and memory “Lark emotional advantage manifests in greater satisfaction with life and reduced vulnerability to mental health problems” Visit the BBC’s Reality Check website at bit.ly/reality_check. or follow them on Twitter @BBCRealityCheck Don’t you envy those people who bounce out of bed early in the morning with a spring in their step? Or maybe you are lucky enough to be one of them! The early bird catches the worm, so they say, and pop culture is filled with variations on the theme that early risers do better in life and get more done, usually with a smile on their face. Countless articles promise us that if only we could drag ourselves out of bed an hour earlier in the morning, we’d…

OTHER MIND - READING TECH NEURALINK Elon Musk’s much-vaunted neurotech start-up requires implantable probes that work as a brain-computer interface. The actual technology remains secretive, but in April 2021 the company demonstrated a chimp using Neuralink to play a game of Pong. OPENWATER This start-up combines electro-optical technology, lasers and holographies to produce non-invasive imagery of the brain, as well as other organs or tumours, in incredible detail. NEURAL DUST Sometimes described as a Fitbit for the nervous system, neural dust refers to tiny implantable sensors that might pave the way for ‘neuroceuticals’. These are diagnostic or therapeutic technologies that work by remotely activating dust-sized devices in the body. NEUROSCIENCE The injectable nanosensor that will one day read your thoughts Mind-controlled machines, minus the wires-in-your-brain bit A new kind of…

Scientists are a cautious bunch, fond of a caveat even when describing their own research. “Our favourite expressions are ‘Yes, but…’ and ‘On the other hand...’ and ‘It remains unclear...’” says gene editor Dr Fyodor Urnov. “So please add all of that to what I’m about to say. If CRISPR realises 10 per cent of what we practitioners of gene editing dream it to be able to do, it will rival the greatest advances in the history of biomedicine as a technology to impact public health.” Urnov is talking via a crackly Zoom link from his office at the Innovative Genomics Institute (IGI) in Berkeley, California, which is at the forefront of what may prove to be the defining scientific breakthrough of the 21st Century. CRISPR is a genome editing…

Cannabis has been around for an awfully long time. There is evidence that it was being used in China as a medicine as long ago as 2600 BC, and I’m fairly sure that at least some Chinese people would have been using it recreationally. But what has happened over the last few years is unprecedented, with an enormous surge in interest in cannabis-related products, to the point where it is being added to everything from dog food to chocolate to shampoo. The problem with all this hype is there is remarkably little evidence about genuine effectiveness. It is certainly an interesting plant, containing more than 500 different compounds, many of which interact with ‘cannabinoid’ receptors in our bodies. One reason why cannabis has such wide and varying effects is because…

1. LAND, EXPLORE, DRILL Launched in July 2020, NASA’s Perseverance rover successfully landed in the Jezero Crater on Mars in February 2021. The roughly hatchback-sized rover represents the first leg of humanity’s first round trip to another planet. The rover will use its drill to collect rock and soil samples and store them on the planet’s surface. 2. SEAL AND DEPOSIT Any samples Perseverance collects will be in sealed tubes that the rover will deposit on the planet’s surface, essentially leaving a trail of breadcrumbs behind it as it explores the Martian surface. Future missions to Mars – collaborative efforts by NASA and ESA – will follow the trail left by Perseverance, to retrieve the samples and return them to Earth. 3. SET OFF THE SECOND WAVE The next stage…

Getting to space: it ain’t easy – each kilogram needs an estimated 32,900,000 joules of energy just to reach low Earth orbit. Despite this hurdle, humans have launched vehicle after vehicle through the atmosphere and into space. But which is heaviest? These are the spacecraft with the largest mass to have flown in Earth’s orbit and beyond. 1 INTERNATIONAL SPACE STATION Space station, made of 16 pressurised modules In service: 1998-present 419,725KG (2011 size) 2 MIR Russian space station In service: 1986-2001 140,000KG 3 SPACE SHUTTLE US orbiter vehicle In service: 1981-2011 110,000KG (Gross lift-off mass of Endeavour) 4 BURAN Russian uncrewed spaceplane In service: 1988 105,000KG (Orbiter vehicle mass) 5 SKYLAB US space station In service: 1973-1979 77,000KG 6 APOLLO COMMAND AND SERVICE MODULE US lunar spacecraft In service:…

Many people, from your mum to Instagram health gurus, have touted the benefits of having some friendly bacteria in your guts. However, little is said about the balance of your intestinal fungi, which could have just as much impact on your health. At least, that’s what’s been shown by an intriguing new study from the University of Utah Health. In experiments with mice, researchers found that while fungi can thrive in a healthy gut, they may also cause intestinal damage leading to inflammatory bowel disease (IBD). To reach this finding, the researchers analysed the makeup of the yeast Candida albicans – one of the main species of fungi that are found in the human gut – in the intestinal systems of mice. They discovered that although the mice populated with…

Dogs are more than just pets; they’re a member of the family… right? If so, you’d think that they’d want to look after you just as much as you look after them. But, unfortunately, a study has found that this may not be the case. Dogs won’t give food to a human, even if that person gave them some food first, researchers at the University of Veterinary Medicine in Vienna, Austria, have found. Previous studies have shown that dogs recognise cooperative and uncooperative humans, and that they would help dogs that had helped them previously. So, the team expected to find that their test subjects would put these two things together and show ‘reciprocal altruism’ – that is, doing a good thing in return – to a human who had…

Scientists at Nottingham Trent University have developed a method of using scans of cancer patients’ organs to 3D print realistic models so that surgeons can rehearse procedures before they take place in real life. The technique recreates the individuality of a patient’s organ, with blood vessels, tissue and any tumours all being included in the completed model. 1. The model liver was constructed using existing 3D scan data taken from an anonymous cancer patient. 2. The team used a combination of synthetic fibres and gels to 3D print an accurate model of the organ, layer by layer. 3. As the process accurately recreates an organ’s internal structure, the model allows surgeons to use real tools to practise complicated procedures such as endoscopies. 4. The completed liver model has a texture…

In June, rewilding charity Trees for Life brought a case against NatureScot, Scotland’s nature conservation agency, for allowing farmers to kill wild beavers. It argues that NatureScot is breaking the law by granting beaver control licences too liberally. The judicial review is seen as a key test case for rewilding campaigners who want beavers to spread further across Scotland and are pushing for the reintroduction of predators such as lynx. Steve Micklewright, chief executive of Trees for Life, says his organisation believes licences to kill beavers should only be issued as a last resort when all other options, including relocation, have been considered. “We also believe that if lethal control licences are required, the number of beavers that can be shot under each licence should be stated, rather than left…

When we die, nature wastes no time in disposing of us. Within minutes, our enzymes get to work on our tissues, breaking down proteins and fats. Not long after, microbes that once inhabited our gut move through our body via our blood and begin the process of putrefaction that liquefies our organs. Our soft tissues usually disappear completely within five years to a decade, leaving nothing but bones and empty spaces – exactly what archaeologists expect to find when they’re dealing with human remains. That’s why, when an archaeologist turns over a skull, the last thing they imagine being confronted with is a brain. But it does happen. When the conditions are exactly right, when death occurs in a particular way, the brain can survive for hundreds and sometimes thousands…

IS TOO MUCH TESTOSTERONE MAKING ME SUCH A GRUMPY OLD MAN? Don’t get angry, but it’s the other way around – a low testosterone level is likely to cause irritability. While the term ‘male menopause’ is used for the condition, this phrase is a bit misleading – there isn’t usually a sudden drop in testosterone in middle age like there is for oestrogen in women. Testosterone levels do fall with age, but the decline is gradual – less than 2 per cent a year from about the age of 30 – and it doesn’t usually cause any issues. Rarely, testosterone can drop to a level that causes symptoms like tiredness, decreased sex drive, problems maintaining an erection, and irritability. But it’s not that common. In 2010, the European Male Ageing…

DOES MY HEART STOP BEATING WHEN I SNEEZE? Aaaaachooo! Sneezing, also known as sternutation, is the rapid and involuntary expulsion of air from the lungs through the nose and mouth. When you inhale before a sneeze, the pressure in your chest increases. Then, when you exhale during the act, the pressure drops. This causes a fleeting change to the heart rate, which quickly corrects itself. So, although you may feel like your heart has skipped a beat, the trusty muscle does not stop beating. Sneezing can be good for you because it helps rid the body of respiratory irritants, such as pollen and dust. However, suppressing a sneeze, by holding your breath or pinching your nose, might even be bad for you. One computer simulation found that, compared with a…

HOW CAN I MAKE BEDTIME EASIER? There’s a genetic component to our need for sleep, so the number of hours varies between families. However much sleep your child needs, they’re far less likely to get it if they’re checking their screens at bedtime. In a 2019 study of 6,000 adolescents, those who used their phones in bed were likely to get to sleep later and to have less refreshing sleep. Most of us, adults and children alike, aren’t getting enough sleep. But research shows that consistent bedtime behaviour work wonders. An online survey of over 1,000 families showed that a regular routine leads to better sleep for all the family. It doesn’t matter what that routine consists of, as long as it’s consistent. Sleep patterns are a matter of habit.…