The solutions to today’s puzzlesOn my puzzle blog earlier today, I set you the following puzzles:1) What is numerically interesting about April 25, 1849 - the date of birth of the German mathematician Felix Klein - and why is this year’s anniversary particularly noteworthy? Continue reading...

Shouldn’t policy be based on evidence – not the other way around?The future seems rosy for Jeremy Hunt. In his newest letter to social media firms, he envisions a future where every child gets a state-imposed and universal social media limit, similar to the alcohol units recommended by government. After a child surpasses a set cutoff point, their social media access is stopped for the day. Hunt makes it seem easy, practical, and better for children and parents alike.There is just one glaring problem. This drastic policy still needs the scientific evidence to back it up. Hunt announced yesterday that his chief medical officer will be taking charge of this. Well, as a scientist working in this area, I can tell Dame Sally Davies now: the evidence this policy needs doesn’t exist. If she is not willing to ignore large parts of the scientific literature or exaggerate a minority of low-quality studies, her job to find the amount of “science” to back up such significant state intervention will be impossible. And, to insert an important side-question, shouldn’t policy be based on evidence – not the other way around? Continue reading...

A one-sided storyUPDATE: The solutions are now up hereHi guzzlers,Today’s puzzles are in honour of the German mathematician Felix Klein, who was born this week 169 years ago, on April 25, 1849. Continue reading...

Fertile breeding conditions caused by hottest summer since records began leads to surge of rats and miceA record-breaking long, hot summer has led to a tenfold explosion in New Zealand’s rodent population, with the country’s urban areas worst hit.The 2017-2018 summer in New Zealand was the hottest since records began, and fertile breeding conditions have led to a surge in rat and mice numbers. Continue reading...

The constellation Leo dominates the southern sky, with Regulus its brightest starOne of the most prominent constellations in the spring sky is Leo. During the winter, it has climbed out of the eastern sky and now dominates the south. The constellation is one of the oldest to be recognised in its current form. The Mesopotamians recognised this grouping of stars about 4,000 years ago. Continue reading...

Thanks to a genetically engineered enzyme, a bug that eats plastic bottles developed a much bigger appetite for our rubbish. It is a hopeful signEvolution never sleeps. Before 1970 there can have been no significant bacteria that ate plastic, because there was not enough of that plastic in the world to sustain a population. But in 2016 a group of Japanese scientists discovered a new species, Ideonella sakaiensis, in the samples they were sifting from a bottle-recycling plant, that was able to attack and eat PET, the plastic used in most bottles, almost all of which ends up in landfill or dumped at sea, where it may last for centuries. Everything that rots in nature does so because it is being eaten by bacteria. Most plastics – among them PET – were considered totally impervious to bacterial attack, making them almost indestructible unless burned or crushed. So a bacterium that can consume even one kind of plastic could become a desperately needed ally in the struggle to stop the oceans being choked with plastic waste.What has captured the imagination of the world is that a subsequent group of scientists, who were trying to understand on a molecular level how I sakaiensis breaks down and digests plastic bottles, found the enzymes that it uses and made a slightly different version of one to see what would happen. The new enzyme is much more efficient than the version found in nature, and works on more kinds of plastic. This kind of molecular tweaking of substances, already found in nature, is at the root of another recent scientific breakthrough, the Crispr-Cas9 technique for genetic engineering. It offers some hope that we can use technology to moderate and even to some extent to reverse the impacts that earlier technologies, such as those that make it easy to manufacture billions of tons of plastic, have had on the world around us. Continue reading...

If you live long enough, you get cancer. But without our mutating, blundering cells, we’d never have made it out of the primordial soup…Bob Weinberg of the Massachusetts Institute of Technology has been one of the world’s foremost experts on cancer for nearly five decades. Back when I was a wee graduate student, I lunched with Dr Weinberg at a conference and he told me something that stuck with me: “If you live long enough, you will get cancer.”The inevitability of cancer has made itself painfully clear over the past century. As mortality from almost all other causes has plummeted, cancer rates have skyrocketed. While there is good reason to believe that some aspects of modern lifestyle and diet also contribute, the bulk of the rise in cancer is simply because we are no longer dying from so many other things. Continue reading...

My father, David Bailin, who has died aged 79, was a physicist who was ahead of his time. His best known work was on superconductivity and superfluidity in relativistic fermion systems, inspired by his former Sussex colleague Tony Leggett’s Nobel prizewinning work on superfluid Helium-3. It gained no citations for the first few years, until its importance for neutron stars was understood.His early research was on the weak interaction – the fundamental force behind certain kinds of radioactivity. He showed that the experimental data at the time required the existence of a heavy W boson particle, which was discovered 20 years later. Continue reading...

Pod of orcas spotted between Dunoon and Gourock, thought to be hunting seals or porpoisesA pod of killer whales has been spotted in the river Clyde apparently hunting seals or porpoises.Images and videos have been posted on social media over the weekend of about half a dozen killer whales, or orcas, between Dunoon and Gourock. Continue reading...

Ultrasound technique overcomes problems with current methods to diagnose the most common cancer in menScientists have announced the development of a highly accurate and reliable technique for diagnosing prostate cancer. The Dundee University-based team say they have used an ultrasound process called shear wave elastography (SWE) to detect prostate tumours. The method is non-invasive and cheaper than current detection techniques.Prostate cancer has become the most common cancer in men in the UK. One in eight men will develop the condition at some point in their lives with more than 47,000 new cases being diagnosed every year. Men aged 50 or over, men with a family history of prostate cancer, and black men are at greatest risk of developing the condition. Continue reading...

We think nothing of sharing personal information with tech giants so why are we so suspicious about our health records?Half of us born after 1960 will be told we have cancer at some point in our lives. Virtually no one will go through life untouched by the disease, whether as a sufferer, a survivor or supporter. So every year, millions of us lace up running shoes, bake cakes and cultivate moustaches in memory of loved ones to raise the cash needed for cancer research.But money is not the only critical ingredient in developing new cures. An important constraint on the pace of progress is the lack of large datasets that contain valuable information on how patients are responding to different types of treatment. Continue reading...

When author Elizabeth Day lost a baby and her marriage ended it was her friends who gave her the unconditional love she’d been seekingAs a child, I remember being pretty certain about a few things. I was sure I’d get married. I was convinced I’d write a book. Then I’d have children – two, of course, just like my parents. Preferably girls because they were better.When you’re younger, you assume life will turn out a particular way because you haven’t lived it yet. It sometimes strikes me that getting older is a gradual erasure of the nonchalant confidence that comes with that naivety. Continue reading...

The US researcher – and sci-fi author – on how brain implants will drive the next turning point in human evolutionDr Eric C Leuthardt, 45, is a neurosurgeon at Washington University in St Louis. He is also the co-founder of NeuroLutions, a research laboratory developing direct interfaces between mind and computer. Leuthardt is pioneering the use of electrical brain implants to help restore motor function to the paralysed limbs of stroke victims. He is also helping to develop electrode systems that can directly decode the unspoken “inner voice” of the mind, and use it to direct external action; for example, Leuthardt’s subjects have been able to control the cursor of a Space Invaders video game just by thinking. He has published two science fiction novels aimed at “preparing society for the changes” that his work predicts. He believes that in the coming years neural implants that link the human brain directly to computers to enhance cognitive functions will be like pacemakers or tattoos, used with hardly a second thought. This interview was conducted by phone, when Leuthardt had just dropped off his children at school and was on his way to perform an operation to remove a brain tumour.A direct neural interface with machines has long been a science fiction dream. When did you first get involved in helping to make it happen?

Meet the startup hoping to colonise the final frontier, one zero-gravity 3D printer at a timeDuring the early weeks of his 167-day stint aboard the International Space Station in 2014, astronaut Barry “Butch” Wilmore noticed that a torque wrench was missing. “It’s not uncommon for things to disappear in space,” he tells me over the phone from the Johnson Space Center in Houston. “You just don’t have gravity keeping stuff in place.” Wilmore mentioned the missing tool to Nasa’s mission control as he was tending to a 3D printer, a microwave-sized box that extrudes heated plastic to build up objects layer by layer, which was being tested on the space station.About a week later, Wilmore opened the door to the 3D printer to find a perfect replica of his missing wrench. He was thrilled, a moment captured in a photo that was shared with the world’s media at the time. Until that point, the machine had produced only very simple objects. “This was a printed, all-inclusive wrench, with a ratchet mechanism, that worked,” Wilmore says.

This week, Ian Sample asks: why do humans fight? Can science tell us anything about what drives us to violence?Subscribe and review on Acast, Apple Podcasts, Soundcloud, Audioboom and Mixcloud. Join the discussion on Facebook and TwitterExperts have been fighting about fighting throughout the ages. While theories have emerged to explain why we fight, there isn’t a consensus in the research. In general, theories of war miss the mark for some. So why do we fight? And what can science tell us? Continue reading...

My father distrusted simple judgments, but he did say his novel was about the importance of the rule of law, and the complexity of human beings, says William Golding’s daughter Judy Golding CarverDavid Shariatmadari’s account of my father’s novel Lord of the Flies was a little sweeping when he declared: “William Golding sought to show that boys were, by their nature, little devils” (A real-life Lord of the Flies: the troubling legacy of the Robbers Cave experiment, 17 April) .The boys in Lord of the Flies make quite a good fist of creating a democratic society, at least to begin with. Ralph, the democratically elected leader, admonishes Jack to stick to “the rules”, because “the rules are the only thing we’ve got”. In an interview the author said that the novel was about the importance of the rule of law. It was also about the complexity of human beings. Continue reading...

Revelation astonishes experts, who thought the renowned bird lived out its life in London as a money-spinning curiosityWith its plump head and bulbous beak, the renowned remains of a dodo at the Oxford University Museum of Natural History have long captivated visitors, Lewis Carroll among them. Now researchers say they have uncovered how the dodo died – a discovery that makes the old bird’s past curiouser and curiouser.Researchers used a form of CT scanning and sophisticated software to probe the anatomy and habits of the Oxford dodo - the world’s best preserved specimen of the bird – and discovered the animal was shot in the back of the head and neck with lead pellets. Continue reading...

Space Rocks, an event celebrating astronomy and music, kicks off this Sunday. The twinned nature of the disciplines it celebrates stretch back millenniaSomehow music and astronomy seem to go together. The association was made in the 6th century BC by the philosopher Pythagoras, who suggested each planet made a different sound and that together these notes made up the musica universalis, the harmony of the spheres.Although we no longer think of the planets as singing, the fact that there is mathematical “harmony” in both music and the laws of physics means they remain partners. Continue reading...

World’s biggest sperm bank calls for fewer regulations to revive Europe’s childbirth ratesThe world’s biggest sperm bank has warned the EU that access to donor sperm must be improved to reinvigorate childbirth rates amid the continent’s slump in population growth.Sperm banks across Europe have closed after the enforcement of new EU regulations on staffing levels, executives at the Danish firm Cryos International told European commission officials in a private meeting. Continue reading...

People are copying pets to preserve a physical – and spiritual – connection to dead children. MIT Technology Review reports.When Barbra Streisand revealed to Variety magazine that she’d had her dog cloned for $50,000, many people learned for the first time that copying pets and other animals is a real business.That’s right: you can pay to clone a dog, a horse or a top beef bull and get a living copy back in a matter of months. Continue reading...

Return of Great Caledonian forest speeded up with fungi spores to help saplings flourishThe return of the Great Caledonian forest that once covered much of Scotland’s highlands is being boosted with a special mix of mushroom spores that should help saplings survive better on the hills.Fungi living on the roots of trees play a vital role in the ecology, helping to break down nutrients in the soil. But trees were lost in much of the Highlands many years ago so the fungi vanished too. Continue reading...

Researchers examining extinction of large mammals as humans spread across the world see worrying trendThe cow could be left as the biggest land mammal on Earth in a few centuries, according to a new study that examines the extinction of large mammals as humans spread around the world.The spread of hominims – early humans and related species such as Neanderthals – from Africa thousands of years ago coincided with the extinction of megafauna such as the mammoth, the sabre-toothed tiger and the glyptodon, an armadillo-like creature the size of a car. Continue reading...

The Transiting Exoplanet Survey Satellite will take an elliptical path around Earth to observe stars for evidence of exoplanetsNasa’s next planet-hunting mission has launched from Cape Canaveral air force station in Florida.The Transiting Exoplanet Survey Satellite (Tess) took to the skies at 23.51 BST (18.51 EDT). It was deployed into Earth orbit 49 minutes later, to start a series of manoeuvres that will get it into its operational orbit by mid-June. Continue reading...

Government finally acknowledges the ‘tragedy’ inflicted on thousands of women, and agrees mesh should only have been used as an extreme measureWomen have been exposed to unacceptable risks through the use of vaginal mesh surgery, the government has acknowledged for the first time, as fresh evidence has revealed that thousands of women have suffered traumatic complications.In a parliamentary debate on the use of the implants, Jackie Doyle-Price, junior minister at the Department of Health, said it was a “tragedy” that women who had put their trust in the medical establishment had “come out with the most debilitating injuries”. Continue reading...

Challenging terms such as ‘natural’ is difficult, but the Real Bread Campaign’s win against the chain proves it can be doneWhen it comes to labelling, food retailers run rings around their customers, and mainly get away with it. They weave a lexicon of feelgood terms – “fresh”, “handmade”, “artisan”, “local”, “farmhouse”, “healthy”, “natural” – into their marketing messages, which just happens to encourage us to assume that two and two makes five, or even six or seven. It’s known as the halo effect: by highlighting one appealing selling point you erect a canopy of goodness around the entirety of the product, irrespective of whether it is merited.Challenging such terms is tough. Regulations covering them are sketchy and open to legal argument on a case-by-case basis, which makes the Real Bread Campaign’s latest victory against the Pret a Manger chain all the more impressive. Continue reading...

Scientists have uncovered the secrets of the Bajau people, long-famed for their ability to hold their breath for extraordinary lengths of timeThe secret behind the ability of a group of “sea nomads” in Southeast Asia to hold their breath for extraordinary periods of time while freediving to hunt fish has finally been revealed – and it’s down to evolution.The Bajau people are able to dive tens of metres underwater with no conventional diving aids. Instead they rely on weights, handmade wooden goggles – and a single breath of air. Continue reading...

The ancient city was one of the first archaeological sites to be occupied by Islamic State. Now new photos are revealing the fate of this important site as archaeologists continue to count the cultural cost of IsisThree weeks ago, the Syrian antiquities directorate released new photos showing another devastated archaeological site. Outside Syria the news has received fairly limited press attention, except in France, where Mari, the site in question, is much better known. French archaeologists have been excavating at Mari since 1933, the most recent expedition running until 2010 when the Arab Spring and growing unrest made the site inaccessible. In light of the level of damage which is now evident, perhaps it’s worth sparing a moment to look at why Mari matters to archaeologists, historians and the cultural heritage of Syria.When Islamic State emerged, the part of Deir ez-Zor province in which Mari lies was one of the first areas to fall under its control in early 2014. Under IS, the site suffered an immediate explosion of looting; satellite images revealed the change from archaeological site to lunar landscape in a matter of months. More than 1,500 new looting pits were recorded at Mari between 2013 and 2015, likely representing the removal of a huge quantity of ancient objects, sold into the illegal antiquities market to fund Isis and its war. Continue reading...

Archaeologists in Champ-Durand, France, have found a cow skull with a small round hole cut into itA stone age cow skull boasting a hole the size of a biscuit has been hailed as a first by archeologists, who say the gouge is the earliest evidence of either a veterinary attempt or animal experimentation.Human skulls from around the world, some dating as far back as almost 10,000 years ago, have been found with very similar holes – evidence, say experts, of a cranial surgery called trepanation in which humans scraped away at the skull, or drilled it, to form an aperture. Continue reading...

Forensic science is nowhere near as robust and reliable as many people thinkWe all want to live in a world where there is justice; where wrongs are righted, where the system is trustworthy and just works. But we have seen a growing body of reports that raise questions about that system. I was particularly challenged when I started doing research that was based on a murder case tried in 2002, which centred on the presence of trace particles on the victim and in the suspect’s vehicle. In court, the jury heard that these particles were very rare and wouldn’t last on clothing for a very long time – just for a matter of minutes. This indicated that the victim must have made contact with the vehicle seat shortly before their body was deposited at the site where they were ultimately found. On this basis, the jury delivered a guilty verdict. When we started exploring and carrying out some experiments on these particles we discovered that they were in fact not rare, but abundant. And they lasted a long time on clothing – many hours rather than minutes. The significance of these particles in that case was completely changed by a series of experiments. Continue reading...

19 April 1955 One of the greatest and probably most original of the minds which have created modern science, dies at the age of 76We much regret to announce the death at Princeton, New Jersey, yesterday of Dr Albert Einstein. He was 76. Dr Einstein had entered hospital in Friday for treatment of arterio-sclerosis.Related: From the archive, 19 April 1955: Einstein as a man Continue reading...

Yorkshire’s Jurassic World, at the Yorkshire Museum, includes a pregnant ichthyosaur, a Mesozoic virtual reality experience, and a dinosaur called AlanIf you say the word Jurassic to people in the UK, the chances are that their first thoughts will be of a certain hugely successful film franchise. Most palaeontologists are fine with this, because it gives us an excuse to wheel out our well-honed “all the things that were wrong about the Jurassic Park film” material. If they mention anything else at all, it is likely to be the Jurassic coast, a fantastic piece of tourism branding which ensures that Dorset seaside towns receive a steady stream of fossil-mad families on holiday every summer.Other British Jurassic outcrops are available, however. In Scotland there are Jurassic outcrops up in the Highlands, and sites on the Inner Hebrides are yielding exciting new discoveries. The north coast of Somerset also has some productive areas, and just like the Jurassic coast rocks found at Lyme Regis, these are part of a swathe of Jurassic rocks running diagonally across the UK from the South coast all the way up to Yorkshire, where they are again seen in all their glory on the North-East coast. A new exhibition at the Yorkshire Museum in York, which was opened in March by David Attenborough, celebrates the fossils of the Yorkshire Jurassic. Continue reading...

Australian scientists say new polymer can remove crude oil and diesel from seawater

Eight-year study finds pioneer of paediatrics assisted in Third Reich’s ‘euthanasia’ programmeThe Austrian doctor after whom Asperger syndrome is named was an active participant in the Nazi regime, assisting in the Third Reich’s so called euthanasia programme and supporting the concept of racial hygiene by deeming certain children unworthy to live, according to a study by a medical historian.Herwig Czech, from Vienna’s Medical University, has made the claim in an academic paper published in the open access journal Molecular Autism, following eight years of research into the paediatrician Hans Asperger. Continue reading...

Machines programmed by engineers in Singapore complete job in just over 20 minutes

My mother, Constance Blackwell, an intellectual historian who has died aged 83, played a key role in fostering deeper understanding of the development of 16th- and 17th-century science and philosophy in Europe.As the founder, in 1994, of the International Society for Intellectual History (ISIH), she supported several national and international conferences and saw their proceedings through to publication. According to Constance, innovation in early modern central European philosophy arose from multidisciplinary commentaries on Aristotelian works covering physics, metaphysics, logic, rhetoric and ethics. Continue reading...

In a new Netflix documentary, the tales of 13 female pilots who dreamed of becoming astronauts yet were denied the opportunity by Nasa are finally brought to lightWhen Neil Armstrong clambered down on to the surface of the moon, he famously declared that he had taken “one small step for [a] man, one giant leap for mankind”.Related: Sign up to our Film Today email Continue reading...

In Barcelona, high-tech data platforms generate demand for old-fashioned community development.

For decades, men have had all the glory in space exploration. Imagine how young girls would feel seeing a woman step on to the red planetWhat do the names Kalpana Chawla, Mae Jemison, Valentina Tereshkova and Sally Ride mean to you? Until fairly recently, the names of these female space pioneers didn’t mean much to me. Despite being obsessed with all things space as a six-year-old girl, who thought a day out at the Jodrell Bank Observatory was as exciting as a trip to Disney World, I was never taught about them. I didn’t know that Dr (!) Tereshkova was the first woman to fly into space, that she was 26 when she went, and that when she took off she said, “Hey, sky! Take off your hat, I’m coming!” Nor did I know that Dr Chawla was the first Indian-born woman to go into space and that after she died in the Columbia disaster they named a hill on Mars after her.A senior Nasa engineer, Allison McIntyre, said this week that the first person on Mars should be a woman. And she’s right, because despite the incredible work of many female scientists and engineers involved in space exploration, there has historically been a “space gap”. Continue reading...

When John Brennan used a 17th-century word to describe the US presidency, Twitter went wild – but what does it mean?Rarely does an ancient Greek portmanteau word spark a Twitterstorm. But that’s what happened when the former director of the CIA John Brennan took to Twitter and accused Donald Trump of running a “kakistocracy”. This tweet sparked a 13,700% increase in people looking up the word using the online version of the Merriam Webster dictionary. These curious souls would have found a terse definition: “Government by the worst people.”Related: 'Slime ball': Trump attacks Comey after new book likens president to mafia boss Continue reading...

Scientists say rock fragments that hit the Earth in 2008 contain evidence of a lost planet that was part of the early solar systemDiamonds found in a meteorite that exploded over the Nubian desert in Sudan a decade ago were formed deep inside a “lost planet” that once circled the sun in the early solar system, scientists say.Microscopic analyses of the meteorite’s tiny diamonds revealed they contain compounds that are produced under intense pressure, suggesting the diamonds formed far beneath the surface of a planet. Continue reading...

My wife has terminal cancer. While there’s a place for broadcasters airing their personal stories, their impact can be devastatingWe live in the age of the confessional. In the not too distant past, private and intimate thoughts remained just that – and if we felt we needed to talk, a frank discussion with friends and loved ones often did the trick. But especially when it comes to cancer, this reticence now seems to be dissipating. Social media has turned the private into public and for many, that’s a very good thing. But for my family – and I suspect for others too – it can be difficult, upsetting and sometimes downright damaging.Related: I have prostate cancer. But I am happy | George Monbiot Continue reading...

Ancient woods are being destroyed for development. A consultation is their only hope

Plastic-eating enzymes | Class in the north | Brown cars | Spring politics | Female newsreaders | Comet ThatcherI hope the artificially created enzymes will begin to help clean up the exponential increase in plastic waste (Researchers make plastic-eating mutant enzyme better, 17 April). Maybe better not to let the cultivated variants out into the wild though – and on no account call them Mutant 59...

As an x-ray crystallographer from the late 1940s onwards, my father, Lawrence Brown, who has died aged 95, was one of a select band of British scientists who helped to determine the atomic and molecular structure of crystals.He put the knowledge he gained to good use in the then growing field of synthetic fibres, particularly with the textile company Courtaulds, where he rose to become head of its acetate and synthetic fibres laboratory. There he oversaw work on the development of several new synthetic fibres, including carbon fibre. Continue reading...

A new rule in the US would eliminate food inspectors and lift limits on how quickly pigs can be killed. The impact on workers, animals and consumers would be disastrous

The latest inquiry must discover how thousands of haemophiliacs contracted HIV or hepatitis C from blood products, and why it was covered up for so longIn two weeks’ time Sir Brian Langstaff will take up his post as chair of the public inquiry into contaminated blood and contaminated blood products. Today, World Haemophilia Day, is the perfect occasion to remind Langstaff what the thousands of haemophiliac victims need from this inquiry if they are to get justice.In the 1970s and 1980s more than 4,600 haemophiliacs contracted HIV or hepatitis C after being infected by contaminated blood-clotting products. Much of the blood had been imported on the cheap from US prisons, and taken from high-risk donors (sex workers, drug addicts and alcoholics) who were paid for their blood. As early as 1975, the TV programme World in Action exposed the fact that the NHS was buying this blood and that it had led to a hepatitis epidemic among haemophiliacs. This was before HIV and Aids had been diagnosed. Continue reading...

Review suggests coffee and tea drinkers might have lower risk of developing cardiac arrhythmias• Sign up to receive the top stories in Australia every day at noon Drinking coffee and tea every day may actually benefit people with heart troubles.New research has linked caffeine consumption from the two popular drinks to decreased rates of arrhythmias, or abnormal heart rhythms. Continue reading...

Diet and lifestyle during the ‘pre-conception’ period can profoundly affect the child’s development, researchers findCouples who are obese, as well as those who smoke and drink alcohol, could be risking the health of their future children, say experts who are calling for far more awareness of the effects of modern lifestyles on babies in the womb.A series of three scientific papers in a leading medical journal spell out the consequences of poor diet and lifestyles for the next generation. They urge schools, GPs and nurses to talk to young people and those who may be planning a family about how to be fitter and healthier before they embark on pregnancy. Continue reading...