BBC Science Focus Magazine的July 2021目录

Early beginnings Humans, along with all the primates, carnivores and rodents, have come a long way through natural selection and evolution. The placenta would have played an important role in giving an edge over other animal forms, in the embryonic and neonatal life of the offspring’s early life. Yet after being a medical consultant for four decades with a background knowledge of embryology, I remain completely ignorant of the origin of the placenta (perhaps an unexpected change of a microsomal protein?), and its evolution to the totally indispensable organ it has become today. I would be grateful if you could enlighten us on this topic. Dr Gamini Katugampola Great question! Around 15 years ago, US scientists discovered two human ‘syncytin’ genes which are only active in the human placenta. Both…

A team of researchers from the University of Zurich, Switzerland, have developed a non-invasive infrared scanning technique that allows them to produce images of the fine structure of the brains of living mice in unprecedented detail. Dubbed ‘diffuse optical localisation imaging’, or DOLI, the technique is based upon a method of imaging known as fluorescence microscopy. In fluorescence microscopy, beams of high intensity light are directed at a fluorescent substance known as a fluorophore. The light is absorbed by the fluorophore and then emitted at a lower wavelength. This emitted light can then be filtered out from any surrounding radiation and used to construct an image. The technique has previously been used to image the brains of animals, but it was only able to image small areas at low resolutions…

For many animals, respiration involves breathing in oxygen and breathing out carbon dioxide via lungs or gills. However, there are several exceptions. Loaches, catfish and orb-weaving spiders can breathe through their guts when the supply of oxygen in their environment gets scarce. Now, researchers at Tokyo Medical and Dental University (TMDU) have shown that oxygen can be delivered into the bloodstreams of mice, rats and pigs via their anuses. The technique, known as enteral ventilation, or EVA, could one day be used to help human patients with severe respiratory conditions. “The rectum has a mesh of fine blood vessels just beneath the surface of its lining, which means that drugs administered through the anus are readily absorbed into the bloodstream,” said first author Ryo Okabe. “This made us wonder whether…

Many children’s hospitals already have storytelling programmes that aim to cheer up patients. But new research, published in the journal Proceedings Of The National Academy Of Sciences, suggests that storytelling also has physiological benefits. “Until now, the positive evidence for storytelling was based on ‘common sense’ and taken at face value, in which interacting with the child may distract, entertain and alleviate psychological suffering,” said study co-author Dr Jorge Moll, of D’Or Institute for Research and Education (IDOR), Brazil. “But there was a lack of a solid scientific basis, especially with regard to underlying physiological mechanisms.” The team, based at IDOR and the Federal University of ABC, Brazil, studied 81 children between the ages of two and seven, all of whom were in the intensive care unit at Rede D’Or…

Electrical and biomedical engineer WHAT’S THE BACKGROUND TO THIS RESEARCH? Moore’s Law states that you can cram more and more transistors into a certain area on an integrated circuit chip. And that number’s been growing exponentially for the last 30 or 40 years. It’s primarily been used not to make the chips smaller, but to put more transistors on a chip that’s the same size. So, we’ve gone from chips with a thousand transistors to chips with tens of billions. But another thing you could do with that density is use it to make chips that are very, very small. HOW SMALL ARE WE TALKING? So this is the smallest autonomous single chip system that we know of that supports both power and bidirectional communication – it’s roughly 300 ×…

You could be forgiven for thinking that the UK is in the grip of a spider emergency. With “spider numbers surging” and “dangerous bite warnings” being issued in the media, people are being “terrorised” and even hospitalised. These headlines have been building for a few years, and the species behind the media arachnid obsession is the noble false widow spider, Steatada nabilis. A relative newcomer to the UK, the species is from the Canary Islands and Madeira. First reported from a site near Torquay in 1879, it spread through southern England, building up from the 1980s to become quite abundant, particularly in urban areas. It has also been expanding its range northwards. So, although the lurid headlines are recent, the species has been around in many parts of the country…

…bioethanol fireplaces Although it’s hard to deny the charm of a log burner, it looks like their days are numbered as the government looks set to ban the most polluting fuels used in them to curb emissions. There is a greener alternative – a biofuel burner. These fireplaces from Danish company Le Feu burn bioethanol, an alcohol produced from biomass like plant waste or straw. This burns cleanly, while providing enough heat to warm a room of 20m², the company claims. You don’t need a chimney to install one, although Le Feu recommends cracking a door open to maintain airflow. Unlike your old log burner, you can move this ecoburner around and get it to face you or take it outside. We trust our readers are smart enough not to…

Most new gadgets get the ‘smart’ moniker slapped on the side of the box, but are we getting any closer to a truly smart home? “People don’t want a smarter home, they want a better home,” says Jamie Siminoff, founder of one of the smart home’s most recognisable brands, the Ring video doorbell. Siminoff invented the gadget to see who was at his front door when he was working in his garage. To date, the smart home has been most successful when it presents a simple solution to a tricky problem and when it makes something just, well, better. A smart thermostat that remembers to turn the heat down when you go out; a connected lock you can unlock remotely to let your nan in when you’re running late; a…

SPIDER-TAILED HORNED VIPER By the time you see the spider-tailed horned viper, it’s probably too late. At least if you’re a bird, that is. Its mottled beige and white body is brilliantly camouflaged against the shimmering backdrop of gypsum and limestone rocks in its natural habitat in Iran – all except for the very tip of its tail, which has evolved into an elaborate lure for unsuspecting birds. As the name suggests, spider-tailed horned vipers have a unique growth at the tip of the tail that is covered in long thin scales resembling spider legs. They expertly wiggle this bait around to mimic the skittering movements of a spider, tricking onlooking birds into thinking they’ve found a tasty meal. But when a bird swoops in to peck at the spider,…

WHY DO I TURN INTO A WEEPING WRECK WHEN I’M HUNGOVER? Hangover anxiety (or ‘hangxiety’) has many contributing factors. One of the effects of alcohol is to increase levels of GABA (gamma aminobutyric acid), which sends chemical messages through the brain to inhibit the activity of nerve cells, initially creating a calming effect. As you carry on drinking, alcohol also starts reducing an excitatory transmitter called glutamate, which often leaves you feeling less anxious. So far, so good. But this doesn’t last. As the body registers this new imbalance in brain chemicals, it tries to correct it. This means when you stop drinking, you’re soon left with unnaturally low GABA levels and a spike in glutamate, which leads to heightened anxiety. Glutamate is also needed to lay down memories, so…

The enduring legend of the ‘brown note’ – a sound frequency so low that its resonance through the human body causes spontaneous, uncontrollable pooping – is thankfully no more than a legend. The origin of this hilarious, if unsettling, myth appears to be a spoof article published in 1974, which described a giant horn that apparently gave the entire audience diarrhoea with a rendition of the national anthem at its unveiling in 1850. However, scientists have tested the effects of different sound frequencies on the human body and found no evidence for the infamous brown note.…

Song Of The Reed: Summer This new four-part series blends fiction with fact to offer listeners an insight into the work and science of conservation across the seasons. Recorded in the Strumpshaw Fen nature reserve in Norfolk, the story is voiced by Mark Rylance and Sophie Okonedo (pictured). BBC Radio 4 21 June, 2pm A Pandemic Poem: Where Did The World Go? In a touching and poignant response to the past 18 months, A Pandemic Poem documents the resilience and the strength of communities, through the words of Poet Laureate Simon Armitage (pictured) and the people of Britain themselves. Available on BBC iPlayer now Bees In A Pod In conjunction with BBC Radio 2’s Big Bee Challenge, this new podcast showcases our favourite pollinators in the very best light. Featuring…

You’re having a bubble! Biologists at Binghamton in the US and the University of Toronto in Canada have found that several species of anole lizards have evolved to breathe exhaled air underwater using a pocket of air that clings to their snouts. The team made the discovery after being shocked to observe the lizards spending long periods of time underwater, sometimes up to 16 minutes, despite being only semi-aquatic. “We found that semi-aquatic anoles exhale air into a bubble that clings to their skin,” said lead author Chris Boccia, who completed the work while studying at the University of Toronto but is now based at Queen’s University. “The lizards then re-inhale the air, a manoeuvre we’ve termed ‘rebreathing’ after the scubadiving technology.” The researchers found that all of the anoles…

Here’s news that should get your blood pumping: researchers from Vienna’s Austrian Academy of Sciences have grown tiny, 3D heart-like organs in a Petri dish. Made from human stem cells, these sesame-seed-sized cardiac models even beat like the real thing. Significantly, unlike previous versions of these tiny heart organs (called cardioids), the scientists didn’t use artificial scaffolding to bind the cells together. Instead, the cells organised themselves to grow a hollow chamber. While useful to earlier studies, cardioids created with the old scaffolding technique did not show the same physiological responses to damage that a fullsized human heart does. In an embryo, human organs develop from stem cells through a process called self-organisation. This is where cellular building blocks interact with each other, move and change shape until an organic…

Bad news for anyone who thought the Galaxy was one of the cool, hip neighbourhoods of the Universe: new research by Australian scientists suggests the Milky Way is far more normal than astronomers had previously thought. For the first time, a galaxy similar to our own was studied in detailed cross-section. The galaxy’s structure, according to the team from the University of Sydney, is a lot like the Milky Way, which forces us to reconsider what we know about our own cosmic neighbourhood. The spiral structure of the Milky Way consists of two layers of stars, one thick and one thin. The thick layer features mainly ancient stars with a lower ratio of iron to hydrogen and helium. The thin layer, which includes the Sun, is home to younger stars…

Ambient computing relies on data points to understand your needs and that data comes from sensors. The more data the smart home has, the more context it can create, and the smarter it can be. Smaller, cheaper, lower powered, more robust sensors make developing smart home tech easier and more scalable, plus smarter sensors provide more context. “The big advancements are going to come as we have more data,” says Siminoff. “But if you just give someone a lot of data without any context or without really analysing it for them, then they’re not going to use it, which means that it doesn’t matter.” But no one wants to install hundreds of sensors or dozens of cameras in their homes, Instead, fewer, smarter sensors will give us a clearer picture…

When the Chicxulub asteroid hit the Earth 66 million years ago, various effects combined to kill the dinosaurs. No doubt many dinos, particularly those within 1,600km or so of ground zero, would have died instantaneously. Others would have died over the next few hours, days and weeks from the heat pulse, tsunamis and earthquakes. The final nail in the coffin was a years-long nuclear winter followed by millennia-long global warming. By about 25,000 years after the asteroid, there are well-dated fossil assemblages devoid of dinosaurs, but overrun with their inheritors: mammals.…

HOW CAN I SEE THE MILKY WAY? WHEN: SUMMER (MAY-OCTOBER) In 1994, a power cut in Los Angeles plunged the city into darkness. With the sudden lack of light pollution, a strange glow appeared in the night sky, causing some concerned citizens to call the emergency services. The silvery cloud they were seeing for the first time? Their own galaxy. Those LA residents aren’t alone in not seeing the Milky Way before. A third of people around the world can’t see it because of light pollution. But the good news is, if you travel somewhere dark and let your eyes adjust, you can still see the magic of the Milky Way. Our Solar System is part of the Milky Way, which is a spiral galaxy. We sit on one of…

HOW DO MOUNTAINS FORM? Most mountains owe their existence to the movement of tectonic plates, vast sections of the Earth’s crust. Where two tectonic plates converge, they buckle and fold, resulting in the most common type: fold mountains. The Himalayas, for example, result from the Asian and Indian plates slowly colliding. Block mountains are created when the pressures between plates allow cracks (faults) to appear, with huge slabs of rock being thrust upwards. Volcanic activity can also produce mountains. As a volcano erupts, the buildup of molten rock can form peaks. Sometimes, the rising magma can remain trapped underground, causing the surface to swell in a dome shape. With tectonic plates typically moving just three to five centimetres per year, mountains slowly take shape over tens or hundreds of millions…

ACROSS 1 Reliable outbuilding (6) 5 Drunken chat after head of broadcasting gets consignment (5) 9 Lettuce as a shipping hazard (7) 10 Gold rug returned to fortune-teller (5) 11 Small vegetable, glossy (5) 12 A no-good shelter outside a line (7) 13 Father’s attempt at filo, say (6) 15 Equal to time and distance (6) 18 After games start, kittens twinkle (7) 20 Deity takes Georgia to be heathen (5) 23 Insults sailor getting employment (5) 24 Eccentric CIA operation is from the heart (7) 25 Time to tear into fashion (5) 26 Assembly of seat constructed, having directions (6) DOWN 2 Article with yours truly as subject (5) 3 Tumbler has right to wave (7) 4 Heavy front, missing number (6) 5 Muscle and bravado initially overturning new…

Brontosaurus burgers for everyone I was reading the ‘In numbers’ section in Discoveries which said “Eating meat three or more times a week increases risk of various illnesses”. Our ancestors did eat meat and very little veggies/fruits/grains. So, are the risks due to processed meats/foods? Or is it due to lack of exercise, modern lifestyles, less physical jobs, etc, etc? I found this science soundbite very unscientific and not useful. Jan Voelker, Gahanna, Ohio The illnesses in question were heart disease, pneumonia, diabetes, diverticular disease, colon polyps, gastro-oesophageal reflux disease, gastritis, duodenitis, and gallbladder disease, and the study comes from an analysis of the health records of nearly 500,000 British people who provided data for an average period of eight years – a pretty robust study. The meat in question…

STRESSED-OUT STUDENTS Scientists at the University of Washington have found that spending time with therapy dogs can help to improve stressed-out students’ thinking and planning skills, with effects lasting for up to six weeks after the end of the six-week programme. VEGETARIANS Eating a plant-based or pescatarian diet may help to reduce the risk of developing moderate to severe COVID-19 infection by 73 per cent and 59 per cent respectively, an online survey of 2,884 frontline doctors and nurses, has found. SWEET MAKERS Shoppers spend around £1.75 less on sweets and desserts when food shopping online compared to in-store, a study at the Harvard T.H. Chan School of Public Health, Boston, has found. This is due to in-store shoppers being more open to impulsive purchases, they say. BEES A study…

Astronomers have found traces of heavy metals in the atmospheres of all of the comets they have studied over the last 20 years – including 2I/Borisov, the first comet to visit from another solar system. Heavy metals like iron and nickel are often found in comets, but only in their dusty and rocky interiors. However, solid metals usually don’t sublimate – turn from solid directly to gas – at the low temperatures found in the atmospheres of distant comets. Heavy metals as gases had only previously been observed in much hotter environments, such as evaporating comets as they passed by the Sun, or in the atmospheres of ultra-hot exoplanets. Belgian scientists were therefore surprised to find trace amounts of the two heavy metals in comet atmospheres throughout the Solar System,…

WHAT DID THEY DO? Researchers at the University of Kent took 20 tardigrades, put them into a state of hibernation by freezing them, placed them inside water-filled nylon cylinders, and then fired them at sand targets at breakneck speeds using a high-powered light gas gun. WHY DID THEY DO THAT? The team wanted to know if the tardigrades, which are the only currently known animal capable of surviving in outer space, could potentially endure a trip across the cosmos on an asteroid or comet, and seed life on another planet – a theory known as panspermia. WHAT DID THEY FIND? The tardigrades were unable to survive being shot at speeds higher than 900 metres per second, slightly less than the speed of 1,100 metres per second reached by a typical…

Billions of periodical cicadas emerged from the ground in early June across 15 states in the US, from Georgia in the south to New York in the north. The insects spend most of their lives as nymphs living less than a metre beneath the surface, feeding on sap from tree roots. Then after either 13 or 17 years, depending on the species, they emerge in vast numbers for a brief adult stage, mate and die. There are 15 ‘broods’ in total, which are grouped according to the year in which they emerge. Brood X consists of all three 17-year species, and is the largest and most impressive cicada emergence. So why do they emerge every 17 years? “For a long time the explanation was that the prime-numbered 17year cycle, and…

Combustion-engine vehicles are viewed as enemies of the environment and it’s easy to see why. By burning fossil fuels, every motorcycle, car, van and lorry adds to air pollution and contributes to climate change. It’s why governments are encouraging drivers to switch to more environmentally friendly electric vehicles (EVs). But while combustion-engine vehicles are an enemy in terms of emissions, they’re currently more of an ally when it comes to recycling. The lead-acid batteries found in combustion-engine cars are easily and widely recycled, says Dr Daniel Reed, a lecturer in materials chemistry at the University of Birmingham. “Lead-acid batteries are the most recycled consumer product globally. [The technology is] mature and standardised so it doesn’t matter who makes your battery or which car you own because the battery conforms to…

“RETRO-FUTURISTIC, BLIMP-STYLE VEHICLES MIGHT JUST REVOLUTIONISE AIR TRAVEL” What if you could fly with a fraction of the carbon emissions of a conventional aeroplane? What if you could cruise through the clouds with almost zero noise? And, what if you could board your aircraft without first having to navigate a sprawling airport and all its associated infrastructure? That’s the elevator pitch for a new generation of airships, the retro-futuristic, blimp-style vehicles that might just revolutionise air travel in the coming decade. Dotted around the world, companies from small start-ups to aerospace giant Lockheed Martin are building lighter-than-air, modern-day Zeppelins with a broad range of applications in mind. One British company, Hybrid Air Vehicles (HAV), recently laid out plans for a series of short-haul flights that would enable city-hopping trips aboard…

NASA’S DAVINCI+ AND VERITAS MISSIONS, AND ESA’S ENVISION MISSION, WERE RECENTLY CONFIRMED. WE’RE OFFICIALLY GOING BACK TO VENUS. WHY’S THAT SO EXCITING? There’s two reasons. The first is that we haven’t done it in a while. When I say we, I mean the United States. The Japanese space agency has the Akatsuki orbiter, which is a climate atmosphere focused orbiter that’s been studying Venus for the last five years. And there have been probes sent by ESA that have studied Venus from orbit. Venus used to be the poster child for planetary exploration. We were interested in it because it was a big, rocky world right next door. It’s closer to Earth than Mars. It takes less time to get there. And the optimal alignment for launches happen more frequently…

YOUR QUESTIONS ANSWERED … HOW LONG DID IT TAKE THE DINOSAURS TO GO EXTINCT? … WHY DOESN’T MY HEART GET TIRED? … WHY DO I TURN INTO A WEEPING WRECK WHEN I’M HUNGOVER? … HOW CAN I SEE THE MILKY WAY? … CAN WE TURN POISONOUS PLANTS INTO EDIBLE CROPS? … WHAT IS THE AVERAGE COLOUR OF THE UNIVERSE? … WHAT WOULD HAPPEN IF TWO GAS PLANETS COLLIDED? … HOW DO DESERTS FORM? … IS THERE REALLY A SOUND THAT MAKES YOU POOP YOURSELF? Email your questions to questions@sciencefocus.com or submit on Twitter at @sciencefocus OUR EXPERTS DR CLAIRE ASHER Science journalist ABIGAIL BEALL Science and astronomy writer DR STEVE BRUSATTE Veteran palaeontologist ALEX FRANKLINCHEUNG Environment and climate expert DR ALASTAIR GUNN Astronomy and space expert DR EMMA DAVIES Chemistry…

In a 2002 study, astronomers found that the light coming from galaxies (and the stars within them) – alongside all the visible clouds of gas and dust in the Universe – when averaged, would produce an ivory colour very close to white. They named this colour ‘cosmic latte’. The ‘beigeness’ of the Universe is because there are slightly more regions that produce red, yellow and green light than those that produce blue. Averaged over the entire sky, however, this beige colour is diluted and appears almost, but not entirely, black.…

Mountain ranges can create deserts by preventing moist air from reaching certain areas. Known as the ‘rain shadow’ effect, this phenomenon has played a part in the formation of many arid landscapes, including the Mojave, Gobi and Atacama deserts. 1 EVAPORATION Warmed by the Sun, water evaporates from oceans and other bodies of water, entering the atmosphere as water vapour and forming clouds. This warm, moist air is swept inland by winds. 2 UPWARDS WINDS If the prevailing wind passes through a mountain range, warm, moist air is forced upwards. As it rises, it expands and cools. As colder air is not able to carry as much moisture, the water condenses out, falling as rain or snow. This is known as orographic precipitation, and typically supports lush vegetation on the…

INDOOR AIR POLLUTION IS WIDESPREAD. It takes many forms, from the tiny particles that are emitted when we cook or clean, to the spores released by mould when it’s damp, and the chemicals that are embedded in our furniture. THE POSSIBLE IMPACT ON HEALTH IS CONCERNING. Small particles that are inhaled can travel to the lungs and cause problems. Studies suggest that indoor air pollution is linked with an increased risk of certain respiratory problems, such as asthma and bronchitis. PUT IT ON THE BACK BURNER. We know that cooking releases particulates into the air, and that levels can remain elevated long after cooking is finished. Open a window when you cook and use the extractor fan if you have one. Put the pot on the back burner, where it…