Indholdsfortegnelse for February 2023 i BBC Science Focus Magazine

Increasing evidence suggests that sitting down too much can put our health at risk. According to the NHS, being inactive is linked to an increased risk of type 2 diabetes, some forms of cancer and early death. Due to this, its advice is to “move more, sit less”. But how often should we be getting up from our chairs and for how long do we need to move? Now, researchers based at Columbia University, New York, have an answer: taking a five-minute walking break every half an hour can offset some of the harmful effects of prolonged sitting. The team had a group of 11 participants sit in ergonomic chairs for an eight-hour stretch, rising only for bathroom breaks or a prescribed period of walking on a treadmill. The exercise…

The presence of a specific biomarker in the blood may be an early indicator of Alzheimer's disease, researchers from Sweden's Karolinska Institutet have found. The discovery could lead to earlier diagnosis of the condition via blood tests, and increase the chance of slowing down its progression. Alzheimer's disease is responsible for around 60 to 70 per cent of all dementia cases. It is caused by beta-amyloid and tau proteins building up in the brain and damaging nerve cells. These build-ups can begin up to 25 years before they lead to noticeable symptoms such as memory loss and issues with speech. The team analysed blood plasma samples from 75 patients, 33 that carried a genetic mutation that predisposes them to develop a rare inherited form of Alzheimer's and 42 without the…

The brightness of the night sky has been increasing by 7 to 10 per cent a year for the last decade, according to a study carried out by the Globe at Night project. This citizen-science campaign involved more than 50,000 observations from volunteers around the world. The problem, according to the report, is ‘skyglow’ – artificial light that keeps the sky in twilight until long after the Sun has set. We spoke to Dr Greg Brown, an astronomer based at the Royal Observatory Greenwich, about what this trend means for laypeople, astronomers and the natural world, and if there's anything we can do to reverse it. HOW BAD IS THE LIGHT POLLUTION SITUATION? ARE WE LOOKING AT A POTENTIAL SCENARIO WHERE FUTURE GENERATIONS WON'T BE ABLE TO ENJOY LOOKING AT…

REALITY CHECK REVIEW ‘Kraken’ COVID variant Mid-life crises Face masks “All the signs are that this is going to cause a bigger wave than we saw in the summer of 2022” Visit the BBC's Reality Check website at bit.ly/reality_check_ or follow them on Twitter @BbCRealityCheck WHAT IS THE ‘KRAKEN’ XBB.1.5 SUBVARIANT? It's the highly transmissible XBB.1,5 subvariant –another offshoot of the Omicron SARS-CoV-2 virus variant – that's been detected in 38 countries to date, including the United Kingdom. Although the United States is currently the hotspot for the subvariant (XBB.1.5 accounting for an estimated half of the country's coronavirus cases), the European Centre for Disease Prevention and Control (ECDC) predicts it will become the dominant form of coronavirus in Europe between February and March this year. So far, just less than a…

…a Jetsons-style future If the show The Jetsons was to be believed, we should all own flying cars by the 2060s. CES 2023 gave a glimpse of that future, with the brand Aska showing off its fourseater flying car. The Aska A5 has a 250-mile (402km) flight range and could, in theory, be driven on the road as well as flown. While just a concept for now, Aska is already working on getting it roadcertified and has hopes to be in operation in the near future. Aska A5 aska.com …a car powered by solar With cities and entire countries closing their doors to new petrol and diesel car all eyes are on electric cars. But while most seem to be following a similar formula, the new kid on the block,…

FEATURE | RHINOS It's early morning in Kenya's Ol Pejeta Conservancy, and under a wide African sky, the last two northern white rhinos left on Earth go for a stroll. From time to time, they pause; tasselled ears twitching, as they lower their broad, flat muzzles to nibble the parched grass. Later in the day, as the mercury rises, they will retire to shady spot and have a siesta, watched over by the armed guards who protect them from poachers around the clock. The rhinos’ names are Najin and Fatu, and they are mother and daughter. Neither can reproduce naturally, and even if they could, there are no males left for them to mate with. This makes the northern white rhino as good as gone, or, as scientists would call…

FEATURE | TIREDNESS There's no denying it: my New Year's resolution hasn't gone well. Just weeks into 2023, I've yet to catch up on what feels like months of lost sleep to become a healthier, more energetic superbeing. My consolation, each dark winter morning as I reach for the snooze button rather than the gym clothes, is that at least it's not just me. In a YouGov poll of adults in Great Britain, published at the beginning of last year, one in eight people said they felt tired “all the time”, and a further quarter were tired “most of the time”. Parents of kids under 18 were the weariest of them all, but childless adults and parents of older children reported feeling wiped out too. Asked about what they'd give…

Globally, people chew roughly 100,000 tonnes of gum each year, but what happens once we've finished with it? Ancient civilisations chewed tree resins such as chicle, but by the 1950s this had been replaced by synthetic gums. Alongside this gum base, modern chewing gum contains softeners such as vegetable oil, emulsifiers that reduce stickiness, fillers like talc to add bulk, plus flavourings, sweeteners, preservatives and colourings. Synthetic gums are generally not biodegradable, but in some cases they can be recycled into new plastic products. New, more sustainable chewing gum alternatives use natural gums like tree sap or rubber…

It used to be thought that many dinosaurs achieved such huge sizes because they grew slowly and continuously, like crocodiles and iguanas do, for a century or more. We now knowthis wasn't the case, and that dinosaurs generally grew fast and died fairly young. We can tell the age of dinosaur fossils by cutting open their bones and counting growth lines; that's because, similarto a tree, dinosaurs laid down one ring of bone growth every year. This technique tells us that Tyrannosaurus rex reached full size in about 16 to 22 years, and usually died at 27 to 33 years old. Other big carnivores called Carcharodon to saurids lived to between 39 and 53 years old. The very largest dinosaurs, the long-necked sauropods like Brontosaurus and Diplodocus, seemed to have…

Our sleep changes throughout our lives in many different ways. When it comes to the amount of sleep that we need, this tends to decrease as we get older. Even though it may seem that teenagers need a lot of sleep, 14-year-olds to 17-year-olds typically need around 8to 10 hours per night, which isn't too dissimilar to adults (7 to 9 hours per night). The timing of our sleep changes as we age. During adolescence, sleep timing becomes later, making an early bed and wake time tricky. Interestingly, this shift in sleep timing occurs in adolescents around the world and is even found in other mammals. Because society is geared towards early start times, young people often have to live out-of-sync with their natural patterns because they have to get…

6.5M The size of the JWST's primary mirror – almost three times that of the Hubble Space Telescope. $10BN The cost to build the JWST. That's roughly four timesthe amount Elon Musk, one of the world's richest people, earns in a year. 13.6 BILLION YEARS The JWST can image events that happened as long as 13.6 billion years ago, just a few hundred million years after the Big Bang. NASA's James Webb Space Telescope (JWST) has come up with the goods again. Images released by the space agency show some of the oldest barred galaxies ever discovered. The galaxies feature so-called stellar bars – elongated bands of stars that stretch from the galaxies’ centres into their outer discs, like those seen in the Milky Way. Two of the six date…

The bright, bubbly blobs seen in this image are supernova remnants – clouds of hot gas and debris that are left behind after the dramatic explosion that occurs at the end of a star's life. Theoretical models predict that there should be far more of them scattered throughout the Milky Way than astronomers have so far been able to observe. However, this new image, produced using data collected by the Australian Square Kilometre Array Pathfinder (ASKAP) and Parkes Observatory's radio telescopes, also in Australia, has uncovered more than a dozen supernova remnants that were previously unknown. This suggests there are many more hiding in plain sight elsewhere in the Galaxy. The image was produced as part of a collaboration between the Australia National Science Agency's Evolutionary Map of the Universe…

DISCOVERIES COMMENT When you hear the word ‘uncertainty’ what do you feel? Scared, anxious, excited or challenged? As humans we have a dichotomy of needs; part of us needs to feel safe, secure and to have some routine, and another part of us needs variety and opportunity. Life presents us with both uncertainty and change, and over the last three years this has been true to an even greater degree. With many global challenges still ongoing, we are likely to face even more of the unknown, so we had better get used to managing it. So how do we detect uncertainty and which part of the brain is responsible for it? Researchers have found that noradrenaline is the key chemical involved in our response to uncertainty. Noradrenaline is a neuromodulator,…

ANALYSIS REALITY CHECK There are many good reasons for feeling a little stress and melancholia when you reach life's halfway point. Before, you might have felt you were on an upward curve — growing physically and mentally stronger with age, learning and earning more. But now, the end is nearer than the start, and you might sense the beginning of a slow descent toward decline and ultimate decrepitude. Layered upon that unsettling shift in perspective, there are some pressing practicalities for many people, such as the demands of children, more responsibility at work, and perhaps caring for ageing parents too. No wonder that many middle-aged people are said to experience a ‘mid-life crisis’ – a term coined by the Canadian psychoanalyst Elliott Jaques, first at a scholarly conference presentation in London…

1700S Demand for 24-hour labour in mills and forges in Britain boosts the use of shift-workers. Centuries later, this kind of disruption to the body's daily rhythms will be linked to an elevated risk of myriad chronic diseases. 1834 Scottish physician Robert Macnish publishes his ideas about slumber in The Philosophy Of Sleep. He notes the negative effects of coffee, anxiety and excessive heat and recommends “plenty of exercise in the open air.” 1880S The first electric lighting systems are installed in houses in the UK, giving people control over the dark-light cycles in their homes. 1913 French physician Henri Piéron publishes The Physiological Problem Of Sleep. The text marks the beginning of modern-day approaches to sleep research and medicine. 1925 Physiologist Dr Nathaniel Kleitman (pictured sitting alongside the bed),…

You may have noticed that ice cubes kept in the freezer fora longtime have atendency to shrink as water is lost. This is because in dry freezer air, ice can transform directly into water vapour without first becoming a liquid, in a process known as sublimation. Ice sublimates in an effort to equilibrate with the vapour pressure of air in the freezer. The water lost from food items during sublimation is redeposited on the food's surface, and on refrigeration cools as ice crystals. The moisture loss means that fruit and vegetables can become shrivelled and dry, while meats can develop a leathery texture and dark spots. The dehydration creates pockets in the food which are then open to the air, accelerating oxidation. In fatty foods, this oxidation can cause unpleasant…

The experience of turning around to find someone staring at you, almost as if you had ‘felt'their stare, is common. Surveys suggest up to 90 per cent of us have had it. Research into the phenomenon goes back to the early days of scientific psychology at the end of the 19th Century. More recently, the ‘sense of being stared at’ has been studied extensively by parapsychology researchers such as Rupert Sheldrake (a believer) and Richard Wiseman (a sceptic). Researchers like Sheldrake believe the effect is real and that we really can feel when someone is looking at us. In his experiments, Sheldrake found a tiny but statistically significant effect in support of the staring phenomenon – his volunteers could judge whether they were being stared at slightly better than if…

A general photographic camera with interchangeable lenses opens the doorto more detailed Moon images. The size of the Moon you'll capture in your image will depend on your lens's focal length. Anything over 200mm will begin to reveal tangible features on the Moon's surface. A 1,000mm focal length lens shows a very detailed full lunar disc. If you can capture the Moon's shape, consider recording the daily change in phase, presenting the results in a calendar format. Be aware that the changing weather can get in the way of projects like this. For the sharpest Moon detail, mount the camera on a platform such as a tripod. Use a remote shutter release to eliminate the need to physically press the shutter button, removing the risk of unwanted camera shake. Set…

ACROSS Attachakeywithdifficulty (5) Onechurchfigureisfound in cups (3,4) Parasitebrokemypearl(7) BoredIscoutarounda nightclub (5) Firmwithstudents that is, a dog (6) Batsmanusefulinthekitchen? (6) Evaluatesketchshowforan audience (6) DraweveryonetoYorkshireriver (6) Permituncultivatedfellowtoleave (5) Associatenewparentwithresistance (7) Adjustedcoveraroundhisfirst new military insignia (7) Smallstrangelyairyland (5) DOWN Telegramaboutregisteredconveyancethat's suspended (5-3) Workoutaproblem(8) Countrygivingleft-wingpoliticianvariable answer (5) Madedrunkbyasweet concoction (4) Nunburnsbeermisused equipment (6,6) Prizeroutinelyhidesnothing(4) Standardsofbehaviourrelatively speaking? (6,6) Dividecapitalgettingover large note (8) Beeryardorganisedpartof sandwich (3,5) BettinginSpainshowscourage (5) Marchedaboutbuilding4) Threatenconflicttothenorth4) ANSWERS For the answers, visit bit.ly/BBCFocusCW Please be aware the website address is case-sensitive.…

EYE OPENER When you're a tiny insect, one of the best ways to avoid getting eaten by predators isto disguise yourself as something else. And treehoppers are masters of mimicry. There are more than 3,000 species of the bugs, many of which have evolved into fascinating shapes that resemble leaves, seeds or even faeces, to camouflage them selves in their treetop homes. This species, from the Alchisme genus, is pretendingto be athorn. Treehoppers feed on plant sap, using their mouthpartsto pierce a hole into stems. Some species will even form a mutually beneficial relationship with ants (the ants lick honeydew excreted by the treehoppers, and protect the bugs from hungry predators in return). “This wasthe first time I had found one so close to athorn and showing its mimicry really…

PHYSICS DISCOVERIES Researchers based at Carnegie Mellon University in Pennsylvania have demonstrated a robot that can melt into a liquid and then reform into its original solid state, much like the terrifying T-1000 from the movie Terminator 2: Judgment Day. The robot's designers showed off its astounding capability by locking it in a cage, before having it melt into liquid, ooze through the cage's bars and then reform on the outside. The team created the phase-shifting hot – formally referred to as a ‘magnetoactive solid-liquid phase transitional machine’ – by embedding magnetic particles into gallium, a metal with a very low melting point of 29.8°C. A phase shift is the process of matter changing from one state – either solid, liquid, gas or plasma – to another. These changes occur…

COVID DISCOVERIES Three compounds that effectively fight COVID-19 infection in human cells have been discovered by researchers based at the University of British Columbia. One, alotaketal C, was derived from a sea sponge collected in Howe Sound, British Columbia, while the others, bafilomycin D and holyrine A, were derived from marine bacteria found in Barkley Sound, British Columbia, and Newfoundland. The discovery suggests that there could be a wealth of COVID-19 medicines waiting to be discovered from natural sources. The team made the discovery after investigating the COVID-fighting properties of more than 350 compounds derived from natural sources, including plants, fungi and sea sponges, collected from around the world over the last 40 years. They bathed human lung cells in solutions made from each of the compounds, then exposed them to…

Just call it the Homer Simpson of black holes. Astronomers using NASA's Hubble Space Telescope have observed a black hole twisting a nearby star into a doughnut shape before consuming it. The violent cosmic occurrence is an example of a tidal disruption event – an astronomical phenomenon that occurs when a star strays close enough to a black hole to be ripped apart by its immense gravitational forces. After the star has been ripped apart, the black hole then devours the resulting gas and debris while belching out intense radiation. Named AT2022dsb, the event is occurring nearly 300 million light-years away from Earth at the centre of the galaxy ESO 583-G004. It was first spotted on 1 March 2022 by the All-Sky Automated Survey for Supernovae (ASAS-SN), a network of…

With fresh concerns over rising flu, Strep A and COVID XBB.1.5 cases, health officials across the UK are scratching their heads over one key question: should we all be wearing masks again? While the UK Health Security Agency has advised adults who are displaying flu or COVID symptoms to wear a face covering, some public figures, such as Scottish First Minister Nicola Sturgeon, have advised all healthy adults to wear a mask in certain settings. But as COVID begins to stabilise in the UK, some scientists have questioned how effective face masks are at controlling current case numbers. “Masks were really heipfui early in the pandemic,” says Prof Paul Hunter from the Norwich Medical School of the University of East Anglia. “But there is evidence that masks were an essential…

NOEL WALTERS, VIA EMAIL An orthopaedic cast is usually removed with a special cast saw, which isan oscillating power tool. While it might look like it could cause a lot of damage, a cast saw is designed with a sharp, small-toothed blade that rapidly oscillates back and forth over a very small angle to cut material. This is quite different to a normal circular saw, which has a rotating blade. A cast saw needs resistance to cut, and is specially designed to slice through rigid materials such as plaster. If it comes into contact with soft tissues such as skin, there is less resistance and so the saw will not cause injury.…

HOW TO SEE A BRIGHT CONJUNCTION WHEN: LATE FEBRUARY AND EARLY MARCH In popular parlance, ‘conjunction’ loosely describes when two or more objects appear close to one another In the night sky. There are several formal definitions of conjunction that describe when objects share the same coordinate values, but for general discussions, being ‘dose’ is enough to qualify the term. The planet Venus is now obvious in the post-sunset sky. A brilliant beacon, it's the brightest of all the planets visible from Earth. Jupiter is second brightest most of the time, except when Mars is brighter for short periods when near opposition. Late February provides an opportunity to spot both Venus and Jupiter as they appear to approach one another in the sky. The action starts from 20 February, when…

More detailed images can be made by coupling an interchangeable lens camera – digital-single-lens-reflex (DSLR) or mirrorlessinterchangeable-lens-camera (MILC) – to a telescope. Adapters for specific camera makes and models can be purchased from astronomy stockists. These consist of a ring with the correct camera fitting. Inside the ring there's a female T-thread; a de-facto standard used in astrophotography. A male T-threaded barrel screws into the adapter, the barrel sliding into the telescope's eyepiece holder. Telescopes tend to have either 1.25-inch or 2-inch barrels; modern ones are supplied with an interchangeable adapter for both sizes. Use the larger 2-inch size, if available. Once coupled, the telescope is like a powerful telephoto lens of fixed f-number. Ideally, use low to mid ISO settings. Keeping exposures short will reduce effects caused by the…