Discovery

The Evidence: Keeping out Covid-19

<p>From flight bans and entry bans to compulsory quarantine and virus testing, most countries have introduced travel restrictions in an effort to control the spread of the virus. But for a virus that knows no borders, do cross-border health measures actually work?</p><p>Claudia Hammond and her panel of global experts answer listeners’ questions and discuss the very latest science about the use of border controls in this pandemic.</p><p>The countries we can all learn from, researchers say, include Singapore, Australia, New Zealand, Taiwan, Vietnam, Thailand and South Korea. Their border policies are said to be consistent and, crucially, integrated with strong domestic public health measures.</p><p>So while we wait for vaccinations, it seems an international vaccination passport will be rolled out very soon, maybe as early as Spring. A digital passport – a golden ticket to travel – could give privileged access to those who have been inoculated. But what are the ethical and scientific concerns of such a move? </p><p>The panel with the answers include Kelley Lee, Professor of Public Health at Simon Fraser University in British Columbia, Canada who is leading an international project to assess cross border health measures, Pandemics and Borders, Dr Voo Teck Chuan, Assistant Professor at the University of Singapore Centre for Biomedical Ethics and a member of the WHO Working Group on Ethics and Covid-19, Dr Birger Forsberg, Associate Professor of International Health at the Karolinska Institute in Sweden and senior physician and health planner at the regional health authority of Stockholm and Marc Lipsitch, Professor of Epidemiology at the Harvard TH Chan School of Public Health and Director of the Centre for Communicable Disease Dynamics in the USA. </p><p>Produced by: Fiona Hill, Samara Linton and Maria Simons Editor: Deborah Cohen Technical Support: Sarah Hockley</p>

The Life Scientific: Giles Yeo

<p>Professor Jim Al-Khalili talks to leading scientists about their life and work.</p>

The power of night

<p>Lucy Cooke meets some of the animal kingdom’s nocturnal inhabitants to understand why it pays to stir once the sun goes down.</p><p>She examines some of the extraordinary nocturnal adaptations from the largest group of mammals, the bats, to the mysterious long fingered lemur, the Aye Aye, to hear why the dark has proved evolutionarily advantageous. In an increasingly crowded planet, could future survival for many diurnal animals depend on a nightlife?</p><p>Producer Adrian Washbourne</p><p>Picture: Honey Badger, Credit: Cindernatalie/Getty Images</p>

The power of one

<p>We humans are a supremely social species, but the coronavirus pandemic has forced many of us into solitary confinement.</p><p>It feels like an unnatural, regressive move, that goes against our collective nature. So why do some species embrace the power of one? And how do they make a success of a solo existence?</p><p>Lucy Cooke meets some of the animal kingdom’s biggest loners - from the Komodo Dragon, to the Okapi and the Black Rhino - to explore the lure of solitude.</p><p>Producer: Beth Eastwood</p><p>Picture: Okapi (Okapia johnstoni), forest giraffe or zebra giraffe, Credit: Jiri Hrebicek/Getty Images</p>

The power of celibacy

<p>You might think that sex is essential for life, but you'd be wrong!</p><p>Lucy Cooke travels to the Hawaiian island of Oahu to meet a community of mourning geckos - self-cloning sisters who have done away with males altogether.</p><p>An array of reptiles, amphibians and fish, along with a host of spineless wonders, from snails to spiders, can reproduce without sex. It's what biologists call parthenogenesis, from the Greek meaning “virgin birth”.</p><p>Many, like the mourning gecko, make great “weed” species. They're explosive opportunists capable of rapidly colonising new territory, as they don’t need to waste energy finding a mate. But without the mixing up of genes, that sex with a male provides, they are less able to adapt and change.</p><p>So sex pays if you don’t want to go extinct.</p><p>Yet there is one self-cloning sister that defies that theory - the Bdelloid Rotifer. Living for millions of years and comprising over 450 species, these microscopic water dwelling creatures have conquered the planet. They get around the drawbacks of no sex, by stealing genes, and escape disease by desiccating and then coming back to life.</p><p>Producer: Beth Eastwood</p><p>Picture: Female Komodo dragon at London Zoo, Credit: Matthew Fearn/PA</p>

The Evidence: The Shapeshifting Virus

<p>News that at least three new variants of SARS-CoV-2 have emerged in three separate continents have sent a chill throughout the scientific community. All viruses mutate but the speed and scale of the changes and the fact they occurred independently, is seen as a wake-up call.</p><p>Genetic sequencing in South Africa first raised the alarm about the version of the virus that was racing through populations in the Eastern and then Western Cape. </p><p>Scientists at the country’s KwaZulu-Natal Research and Innovation Sequencing Platform, KRISP, were struck by the sheer number of genetic mutations, many of which were on the all-important spike protein. This is where the virus binds to human cells and where neutralising antibodies, our immune system’s defences, also mount their defence. Any changes there, researchers knew, could be bad news.</p><p>Genetic sequencers in the UK also identified a new lineage which shares just some of the mutations in the South African variant. Named B.1.1.7 this version tore through populations in the South East of England and is now the dominant strain throughout the country and beyond. Latest estimates suggest is between 30 and 50% more infectious, although exactly how it is more transmissible is still being worked out.</p><p>In Brazil too, news earlier this month of another troubling variant, the P.1. tearing through populations in Manaus, the capital of Brazil’s Amazonas state, where so many were infected in the first wave of the pandemic. Like the version identified in South Africa, this variant also has mutation called E484K on the all-important spike protein. This could make the virus better at evading antibodies, with huge implications for re-infection rates and the new vaccines.</p><p>Claudia Hammond and her expert panel consider what the new shapeshifting virus means for the global goal of herd immunity and an end to the pandemic. And they answer your questions. Please do keep your virus queries coming in to <a href="mailto:the.evidence@bbc.co.uk">the.evidence@bbc.co.uk</a> and your question could be included in the next programme.</p><p>Claudia’s guests include Dr Richard Lessells, infectious diseases specialist from the University of KwaZulu-Natal in South Africa and part of the team that identified the South African variant; Dr Muge Cevik, clinical lecturer in infectious diseases and medical virology at the University of St Andrews in Scotland and a member of the UK’s expert committee NERVTAG (New and Emerging Respiratory Virus Threats Advisory Group); Dr Shane Crotty, Professor for Infectious Disease and Vaccine Research at la Jolla Institute for Immunology, University of California San Diego in the USA and Dr Margaret Harris from the World Health Organisation in Geneva. </p><p>Produced by: Fiona Hill, Samara Linton and Maria Simons Editor: Deborah Cohen Technical Support: Donald McDonald and Tim Heffer</p>

Science Trumped

<p>When US health expert sighed last week that science could now speak again, his sense of relief was shared by many scientists. Since the start of the Trump administration, experts inside the US government's science agencies, and those outside working with them have felt their efforts sidelined. From the coronavirus effort to international relations and the border wall, Roland Pease hears from some of those who have felt shut out of the nation's science conversation these past four years.</p><p>Presenter: Roland Pease</p><p>Picture: U.S. President Donald Trump references a map held by acting Homeland Security, credit: Chip Somodevilla/Getty Images)</p>

Plant scientist Dale Sanders

<p>Professor Dale Sanders has spent much of his life studying plants, seeking to understand why some thrive in a particular environment while others struggle. His ground breaking research on their molecular machinery showed how plants extract nutrients from the soil and store essential elements. Since plants can’t move, their survival depends on these responses. In 2020, after 27 years at the University of York, he became the Director of the John Innes Centre in Norwich, one of the premier plant research institutions in the world. Meeting the food needs of a growing global population as the climate changes is a major challenge. And, Dale says, it’s not only about maximising yields. We need crops that are more resilient and more nutritious. Drought resistant crop varieties, for example. And zinc-rich white rice. Dale talks to Jim about how plant science is helping to feed the world in a sustainable way and why plant scientists don’t always get the recognition they deserve. Producer: Anna Buckley</p>

Astrophysicist Andy Fabian

<p>Professor Andrew Fabian from Cambridge's Institute of Astronomy has spent his career trying to unravel the mystery of how some of the most dramatic events in the universe can profoundly influence its evolution. For over 50 years he’s been examining our universe using X-ray satellites orbiting way above earth’s atmosphere . He’s built up compelling evidence that supermassive black holes at the heart of galaxies are the engines that drive the movement of energy through the universe and provide the building blocks for the formation of new galaxies. They're extraordinary insights, for which he’s now been awarded the 2020 Kavli Prize in Astrophysics, one of the world's most prestigious science prizes.</p><p>Jim Al-Khalili hears how Andy gets to capture epic galactic events in motion to build up a picture of this vast ecosystem - and also how he earned a place in the Guinness Book of Records for discovering the deepest note in the universe – a B flat , 57 octaves below middle C.</p><p>Producer Adrian Washbourne</p>

Marine conservationist Heather Koldewey

<p>Professor Heather Koldewey wants to protect our oceans from over-fishing and plastic pollution. An academic who is not content to sit back and let the science speak for itself, she wants to turn science into action and has found conservation allies in some unexpected places. Working with a carpet manufacturer, she created Net-Works, a business that turns old fishing nets into high-end carpet tiles and she has collaborated with Selfridges department store to give marine conservation a make-over. A research career that began studying the genetics of brown trout in Welsh rivers took her to the Philippines to save seahorses and a job running the aquarium at London Zoo. In 2018, she was made a National Geographic Fellow. Heather tells Jim Al-Khalili why, despite all the challenges to marine life, she remains an ‘ocean optimist’ and how she learned to drop her ‘scientific seriousness’.</p>

Climate meltdown

<p>The year 2020 started with wildfires raging across parts of Australia, exceptional floods in East Africa, and a heatwave in the Arctic. Extremes persisted through the year in the north - where wild fires consumed record areas in Siberia, and the Arctic ice reached record lows. Death Valley saw the highest reliable temperature yet recorded on the planet, while the Atlantic saw the most active hurricane season on record. An extreme year by many measures, and one that could end up as the hottest on record globally. Roland Pease asks what it tells us about global warming.</p><p>Picture credit: Wegener Institute / Steffen Graupner</p>

Hopes and fears for Covid-19 vaccines

<p>Less than a year in, and the first vaccines are already being rolled out, with many more in the pipeline. It is an unprecedented scientific response to the global pandemic and researchers around the world have provided the first hope against one of the most formidable challenges facing humanity in a century.</p><p>Claudia Hammond and her expert panel of guests consider the scale of this herculean effort and answer listeners' questions about vaccine safety, trust, immunity, and long term protection.</p><p>The World Health Organisation has repeatedly said that no-one is safe until we are all safe, so the threat of vaccine nationalism and the purchase of millions of the first vaccine doses by rich countries is something that is concerning everybody worried about equitable vaccine distribution.</p><p>How will the COVAX facility, which is designed to boost vaccine purchasing power for the world's poorest countries, fare in the face of nationalistic purchasing - and will surplus doses be shared so that all seven point five billion of us can get protection?</p><p>And, finally, the scale of the threat from vaccine hesitancy. Any vaccine is only as good as the number of people who will take it to achieve herd immunity. The numbers of those suspicious about a potential Covid-19 vaccine have grown over the course of the pandemic, causing real concern for governments around the world. How can people be reassured that vaccines are safe?</p><p>This month, Claudia's guests include Professor Peter Hotez, Dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston and co-director of the Texas Children's Hospital Centre for Vaccine Development in the USA, Professor Helen Rees, founder and executive director of the Wits Reproductive Health and HIV Institute, the University of Witwatersrand in South Africa, Kalipso Chalkidou, Professor of Practice in Global Health at Imperial College, London and Director of Global Health Policy at the Centre for Global Development and Dr Ève Dubé, a medical anthropologist from the Institute of Public Health in Quebec, Canada.</p><p>Produced by: Fiona Hill, Samara Linton and Maria Simons Editor: Deborah Cohen Technical Support: Tim Heffer and Giles Aspen</p><p>Picture: Covid-19 Vaccination Clinics Open In Surrey, UK, Credit: Leon Neal/Getty Images</p>

Evolutionary biologist Alice Roberts

<p>It’s amazing what we can learn from a pile of old bones. Having worked as a paediatric surgeon for several years (often doing the ward round on roller blades), Alice Roberts spent a decade teaching anatomy to medical students and studying human remains. A niche interest in the collar bone and how it has changed since we evolved from the common ancestor we share with other apes 6 million years ago, led her to some of the biggest questions in science. Who are we? And where do we come from? She is the presenter of several landmark TV series on human evolution and archaeology, such as The Incredible Human Journey and Digging for Britain. And in 2019 she became President of the British Science Association. In conversation with Jim Al Khalili, Alice shares her passion for the bones of our ancient ancestors and of the freshly dead, and describes her own incredible journey from a basement full of medieval bones to an eminent science communicator and public figure.</p><p>Producer: Anna Buckley</p>

Steve Haake

<p>Steve Haake has spent much of his career using technology to help elite sports people get better, faster and break records. He has turned his hand to the engineering behind most sports, from studying how golf balls land, to designing new tennis racquets and changing the materials in ice skates. He’s now Professor of Sports Engineering at Sheffield Hallam University and was the Founding Director of the Advanced Wellbeing Research Centre there.</p><p>Since the 2012 London Olympics, Steve has also been working to improve the health and wellbeing of all of us. As Chair of the Parkrun Research Board he’s heavily involved in this international phenomenon in which thousands of people have sprinted, jogged and stumbled around a 5-kilometre course on Saturday mornings, which he’s shown really does encourage people to be generally more active.</p><p>Jim al-Khalili talks to Steve Haake about how he got from a physics degree to being one of the leading sports engineers in the world, and how we can all improve our health by moving more.</p>

The Space Burrito

<p>Is there a point in space where the Sun could heat a burrito perfectly? asks Will. The doctors tackle this and a plethora of other conundrums from the Curious Cases inbox.</p><p>Featuring expert answers from astrophysicist Samaya Nissanke, cosmologist Andrew Pontzen, and cognitive neuroscientist Sophie Scott.</p><p>Presenters: Hannah Fry &amp; Adam Rutherford Producer: Jen Whyntie</p>

The Zedonk Problem

<p>Today I learnt that tigons and ligers are what you get when lions and tigers interbreed?!’ surprised listener Jamz G tells the doctors. ‘What determines whether species can interbreed?’</p><p>Geneticist Aoife McLysaght studies molecular evolution. She explains the modern definition of a species, built on ideas from Aristotle, Linnaeus and Darwin: a species is a group of organisms capable of interbreeding to produce fertile offspring. Hybrids – such as ligons and tigers – are usually infertile, because their common ancestors long ago diverged into the lions and tigers we know today. However, this definition isn’t absolute, and there are many ways a new species can be formed.</p><p>Hybrids also offer rich study subjects for scientists. Mathematical biologist Kit Yates discusses why he’s been reading research papers about hebras and zorses (horse x zebra) as their patterns offer insights into how cells spread and develop into organisms, building on a prediction made by codebreaking mathematician Alan Turing.</p><p>And it turns out that these hybrids are even more intriguing. As speciation and evolution expert Joana Meier explains, hybrids are not always infertile. Hybridisation can lead to successful new species arising, such as in Lake Victoria’s cichlid fish, who it seems have been having a wild evolutionary party for the last 15,000 years. And the picture gets even murkier when we discover that modern genetics reveals our human ancestors successfully mated with Neanderthals.</p><p>Presenters: Hannah Fry &amp; Adam Rutherford Producer: Jen Whyntie</p>

The Evidence: Pandemic rules: follower or flouter?

<p>Millions of us, across the world, are subject to curfews, stay-at-home orders and lockdowns but what makes us stick to the rules, bend them or ignore them altogether? Claudia Hammond and her expert panel of guests consider the psychology of following the rules. </p><p>Leading social psychologists share research which show that higher levels of trust in leadership translates to more pandemic guidance followed. A sense of “We” not “I”, a shared identity, makes a difference too, as well as identification with the whole of humankind, not just your immediate family.</p><p>But there is danger too, from a “narrative of blame”, where individuals are demonised if they break the rules. Such an approach, Claudia hears, is corrosive to the all-important sense of shared identity and alienates some groups, while making others complacent. </p><p>Also in the programme, what impact can rapid “have you got it” antigen tests which give results in minutes, rather than days, have on the virus? </p><p>Claudia hears from the Cameroon in Central, West Africa, one of the first countries in the world to try mass testing using these rapid diagnostic tests. And she talks to scientists at the forefront of evaluating and modelling how their use could affect transmission of the virus, and daily life for all of us, until a vaccine is available.</p><p>This month, Claudia’s panel of specialists answers BBC World Service listeners’ questions and includes Professor Michael Mina, Assistant Professor of Epidemiology Immunology and Infectious Diseases at Harvard TH Chan School of Public Health in USA, Dr Margaret Harris, from the World Health Organisation in Geneva, Switzerland, Steve Reicher, Professor of Social Psychology at St Andrews University in Scotland, Professor Rolf Van Dick, social psychologist and Vice President of the Goethe University in Frankfurt, Germany and Dr Jilian Sacks, senior scientific officer for Pandemic Preparedness for FIND, the Foundation for Innovative New Diagnostics in Geneva.</p>

The end of everything

<p>Everyone knows about the Big Bang being the beginning of the universe and time - but when and how is it going to end? ask brothers Raffie and Xe from Rome. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. The doctors sift science from philosophy to find out.</p><p>Cosmologist Jo Dunkley studies the origins and evolution of the universe. She explains how astrophysical ideas and techniques have evolved to tell us what we now know about our galaxy and far beyond, from the elegant parallax technique to standard candles. This particular distance measure, which uses stars of a known brightness to work out how far away other objects in the universe are, was discovered by American astronomer Henrietta Swan Leavitt in 1912, who worked at the Harvard University as one of several “computers” – women who processed and calculated data and made significant contributions to astronomy.</p><p>Curious Cases’ universal guru Andrew Pontzen puts this into context. Because the universe is so enormous, it turns out that these measurements are just the first steps on the cosmic distance ladder – a suite of tools that astrophysicists use to determine distances to celestial objects. Scientists know that objects are moving away from us because the wavelengths of light from them get stretched and appear redder in our telescopes – the so-called red shift effect. But having a handle on the distances to and between those objects allows cosmologists to monitor what’s happening to them over time. And it turns out that not only are they getting further apart, indicating that the universe is expanding, but that this process is accelerating.</p><p>So what might happen in the end? Expansion and then collapse – a big crunch? Expansion into the void – a big freeze, or a big rip? Or what if there is more than one universe – might a new one bubble up with totally different laws of physics that would cause our own to cease existing? It turns out that when dealing with predictions for something involving infinite space and time, the possibilities are largely limited by human imagination alone. Ideas are where science starts, but experiments are required to build evidence confirming or rejecting them as fact. The doctors discuss how gravitational wave detectors and quantum computers might one day provide this.</p><p>Presenters: Hannah Fry &amp; Adam Rutherford Producer: Jen Whyntie</p>

Broad spectrum

<p>Autism is a lifelong condition, often seen as particularly ‘male’. Yet a growing number of women, and those assigned female at birth, are being diagnosed as autistic in their 30s, 40s, 50s, and beyond. Writer and performer Helen Keen is one of them, and she’s found this diagnosis has helped her make sense of many aspects of her life, from growing up with selective mutism, to struggling to fit in as a young adult. In this programme Helen asks why she, like a growing number of others, had to wait till she was well into adulthood before finding her place on the autistic spectrum. She discovers that for many years psychologists believed that autism was rarely seen in women and non-binary people. Now it is accepted that people often display autistic traits in different way - for example, they may learn to ‘camouflage’ and behave in a neurotypical way - but at what cost? Helen talks to others like her who have had late diagnoses, and finds out if knowing they are on the autistic spectrum has given them insight into how they can navigate the pressures on them from contemporary society. She also explores how we can value and celebrate neurodiversity.</p><p>Helen also talks to psychologists Professor Francesca Happé, of the Institute of Psychiatry, Psychology and Neuroscience in London, and Dr Steven Stagg of Anglia Ruskin University about their research into autism.</p><p>Picture: Geometric camouflage pattern, Credit: Yuri Parmenov/Getty Images</p>

Birds: singing for survival

<p>As large areas of the world have locked down this year, many of us have become more aware of the birdsong around us. The relative silence has allowed us to listen in. But scientists have known for several years that the birds themselves have been responding to human noise too, by pitching their songs and other calls higher, to be heard over the rumble of our urban life. </p><p>There are several ways in which birds can adapt how they communicate in the face of environmental pressures, but what are the limits to these adaptations? And what can this tell us about how to maximise conservation efforts in the future? Rory Crawford talks to ornithologists and animal behaviourists studying bird species around the world. He finds out how the advance of technology is helping researchers explore birds’ preferences and behaviours in the wild, and hears how one particular bird changed its song, and the new version rapidly spread across North America – “the most viral tweet of all time”, as it’s been called!</p><p>Picture: A Robin [Erithacus rubecula], Credit: Gary Chalker/Getty Images</p>

Digital touch

<p>Claudia Hammond asks if touch can be replicated digitally? What devices exist already and how likely are we to use them? Michael Banissy, co-creator of the Touch Test, neuroscientist David Eagleman and researcher Carey Jewitt look at the possibilities for touch technologies in the future. David has developed a wristband that translates sound into touch for deaf people, Carey looks at the ethics of digital touch and Michael reveals the attitudes from the Touch Test towards digital technologies. If we could replicate the feeling of holding a loved one's hand in hospital would it really be the same? And dancer Lisa May Thomas talks about her experience of extending touch into space and through virtual reality.</p>

The Evidence: Are national lockdowns evidence of policy failure?

<p>As a surge of cases risks overwhelming health services in parts of Europe, Claudia Hammond and experts from around the world examine the evidence behind using lockdowns to supress the virus. </p><p>Lockdowns describe a huge range of actions that many governments took in the first wave of the pandemic when so little was known about where the virus was circulating. But full lockdowns are seen as very blunt tools, a last resort because they can have enormous social and economic consequences. </p><p>Instead a more targeted, localised, smarter response to slow down transmission is recommended, where data about virus circulation informs focussed interventions.</p><p>Also in the programme, The Great Barrington Declaration earlier this month called for an end to current lockdown policies and appealed for the vulnerable to receive “focussed protection” while everybody else “should immediately be allowed to resume life as normal”. The goal, the group of scientists said, should be to minimise deaths and social harm, until herd immunity, or population immunity, is reached.</p><p>The World Health Organisation has described such a strategy as dangerous and counterproductive. Claudia’s guests discuss the scientific and ethical issues raised and consider the scale of global exposure to this novel virus. So far only around 10% of the world’s population have been infected so what would a policy of herd immunity in the absence of a vaccine mean for the remaining 90%?</p><p>Listeners put their questions about coronavirus and the pandemic directly to Claudia and her panel of specialists, which this month includes Dr Maria Van Kerkhove, Technical Lead for the World Health Organisation’s Covid-19 Response; Professor Salim Abdool Karim, a clinical infectious diseases epidemiologist and Chair of South Africa’s Ministerial Advisory Committee for Covid-19; Martin McKee, Professor of European Public Health at the London School of Hygiene and Tropical Medicine and one of the signatories to the John Snow Memorandum; epidemiologist Tove Fall, Professor at Uppsala University in Sweden running the Covid-19 symptom app and virologist Professor Steven Van Gucht, from Sciensano, the Belgian national institute for public and animal health. </p><p>The Evidence is produced in association with Wellcome Collection. Production team: Fiona Hill and Maria Simons Studio engineer: Jackie Margerum Editor: Deborah Cohen</p>

Affectionate touch

<p>Claudia Hammond looks at the neuroscience behind our sense of touch. Why does a gentle touch from a loved one make us feel good? This is a question that neuroscientists have been exploring since the late 1990's, following the discovery of a special class of nerve fibres in the skin. There seems to be a neurological system dedicated to sensing and processing the gentle stroking you might receive from a parent or lover or friend, or that a monkey might receive from another grooming it. Claudia talks to neuroscientists Victoria Abraira, Rebecca Bohme, Katerina Fotopoulou and Francis McGlone who all investigate our sense of emotional touch, and she hears from Ian Waterman who lost his sense of touch at the age of eighteen.</p>

Unwanted touch

<p>Claudia Hammond explores unwanted touch and who we do and don’t mind touching us – and where. She draws on insights from the largest study that’s ever been conducted on the topic of touch – The Touch Test - commissioned by Wellcome Collection. Almost forty thousand people from all over the world chose to take part. Claudia discusses where we draw the boundaries between acceptable and unacceptable touch, at work or in the street, with Dr Amy Kavanagh, a visually impaired activist and campaigner, Joanna Bourke, Professor of History at Birkbeck, University of London and the author of “Rape - a History”, and Dr Natalie Bowling, a psychologist at the University of Greenwich who co-created the Touch Test and has been crunching the numbers. After #meToo and Covid, could unwanted touch even become a thing of the past?</p>

Touch hunger

<p>Claudia Hammond explores our experience of touch hunger, and asks if we have enough touch in our lives. Covid-19 and social distancing have changed how most people feel about touch but even before the pandemic there was a concern about the decrease of touch in society. Claudia and Professor Michael Bannissy of Goldsmiths, University of London, discuss the results of the BBC Touch Test, an online questionnaire that was completed by around 40 000 people from 112 countries. Professor Tiffany Field, Director of the Touch Research Institute at the University of Miami School of Medicine, and Merle Fairhurst, Professor of Biological Psychology at Bundeswehr University Munich, reveal their findings about the impact of touch hunger and how to overcome it.</p><p>John grew up during the Second World War and endured a lack of touch in his childhood. He relates how in adult life he overcame this absence of touch and why touch remains so important to him. And left isolating in London during lock down, flatmates B and Z came up with a plan to stay healthy with a 6 o’clock hug. Hugging releases a mix of anti-stress chemicals that can lower the blood pressure, decrease anxiety and help sleep.</p>

Megadrought in Chile

<p>Drought is a massive problem for Chile. Jane Chambers has been living in the capital Santiago for more than ten years and has seen huge changes in that time. It used to rain frequently in the winter months between June and September and the Andes Mountains which run down the whole of Chile were snow-capped all year round. But that doesn’t happen anymore. Jane reports on the impact of the mega drought on the country and what is being done about it. She talks to climate scientists Sebastian Vicuna, Director of the Global Change Research Centre, at the Catholic University of Chile and to Rene Garreaud, a Professor in the Geophysics Department at University of Chile and Deputy Director of the Center for Climate and Resilience Research, about whether the megadrought is the result of natural weather patterns or of climate change. She meets farmers who are struggling to find pasture for their goats in the village of Til Til, and Francisco Meza, a Professor in the department of agriculture and forestry at the Catholic University in Santiago, who is helping agriculture adapt to low rainfall. And Jane hears about ways to increase the availability of drinking water through small-scale desalination and by capturing moisture from the air. </p><p>Picture: Flows of rivers and reservoirs have reached historic minimums in Chile. A severe drought is hitting the country's central area, making local communities more vulnerable to face the coronavirus pandemic. (Photo by MARTIN BERNETTI/AFP via Getty Images)</p>

The sting in the tail

<p>"What’s the point of wasps?" asks listener Andrew, who is fed up with being pestered. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. Do wasps do anything to justify their presence as a picnic menace?</p><p>Ecologist Seirian Sumner researches social wasp behaviour and champions their existence. Not only do yellow jacket wasps perform important ecological services as generalist pest controllers of aphids, caterpillars and flies in the UK, they have complex societies and may even perform pollination services, making them more like their better-loved bee cousins than many might think.</p><p>However, much remains unknown about wasps’ contribution to our ecosystem. Seirian works with entomologist Adam Hart, and together they run The Big Wasp Survey each summer, a citizen science project dedicated to find out more about UK wasp species and their populations. Prof. Hart sets up an experimental picnic with Dr Rutherford to try and attract some native wasps, and discusses why they are so maligned.</p><p>But in some parts of the world UK wasp species have become a major problem. Just after World War II, having unwittingly chosen some aircraft parts destined for New Zealand as their overwintering home, some wasp queens woke up in the city of Hamilton. With no natural predators or competitors, they quickly established a growing population. Fast forward to today, and by late summer the biomass of wasps becomes greater than all the birds, rodents and stoats in the southern island’s honeydew beech forests. Multiyear nests have been discovered that are over three metres tall and contain millions of wasps. Researcher Bob Brown is digging into wasp nests back in the UK to discover which species keep wasps in check here, and whether they might work as biological control.</p><p>This causes the doctors to ponder the problems of humans moving species around the planet. Accidental or even well-meaning introductions all too often become invasive. As climate change and urbanisation accelerate, wasps may become more helpful in some ways and more harmful in others.</p><p>Presenters: Hannah Fry, Adam Rutherford Producer: Jen Whyntie</p>

The Evidence: Covid lessons for safe school reopening

<p>Claudia Hammond and experts from around the world consider the evidence behind schools, colleges and coronavirus spread. Listeners from India, Cuba, Italy, Brazil, Canada, Hong Kong, France, the USA pitch their questions to the specialists. </p><p>Research so far shows a low risk of transmission but as children and young people return to classrooms across the globe, will that remain the case?</p><p>And Claudia and the team look at that vital role of “test, trace and isolate” when it comes to SARS-CoV-2, something the World Health Organisation describes as the backbone of any Covid-19 response. </p><p>Which countries are getting this right and what can others learn from the best? New research comparing six countries from Europe, Africa and Asia highlights the successes and the failures. </p><p>Plus Kat, a nurse from Kansas City, Missouri gives a first hand account of pandemic response in the USA and then, when she moved to Germany in the summer, from Stuttgart. </p><p>On the panel are Dr Regina Osih, an infectious disease and public health specialist from the Aurum Institute in South Africa who’s working on the country’s Covid response, Dr Young June Choe, paediatrician and assistant professor at Hallym University in South Korea, Gail Davey, Professor of Global Health Epidemiology at Brighton and Sussex Medical School in England, David Heymann, Professor of Infectious Disease Epidemiology at the London School of Hygiene and Tropical Medicine from France and Dr Margaret Harris from the WHO in Geneva. </p><p>The Evidence is produced in association with Wellcome Collection. Production team: Fiona Hill, Samara Linton and Maria Simons Studio engineers: Matilda Macari and Tim Heffer Editor: Deborah Cohen</p>

The seeded cloud

<p>"Could you make a machine to make it rain in minutes?" asks listener Alexander from Hampshire, aged 12. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. Rutherford and Fry dive into the clouded story of weather modification.</p><p>First, we need to decide where and when we might deploy any rain machine. Liz Bentley, Chief Executive of the Royal Meteorological society, takes us through the science, maths and art of predicting the weather. Hannah heads down to the BBC Weather Centre to meet meteorologist Helen Willetts, who takes us through the highs and lows of forecasting.</p><p>And then for the technology itself. Mark Miodownik, scientist and author of Liquid: The Delightful and Dangerous Substances The Flow Through Our Lives, reveals that a technique called cloud seeding has almost certainly been tried in different places around the world for decades. But, whilst it’s supposed to induce showers and even clear the way for sunny spells, the results aren’t always reliable. And even if we can make it rain, Liz explains why messing with the weather may be at our peril.</p><p>Presenters: Hannah Fry, Adam Rutherford Producer: Jen Whyntie</p>

The growling stomach

<p>"Why do our tummies rumble - and when they do, does it always mean we are hungry?" asks listener James, aged 12. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. To get to the bottom of this noisy problem, the doctors tune in to our guts.</p><p>Geneticist Giles Yeo studies food intake and obesity. He explains the wavy workings of our digestive system, and how those audible rumbles are a sign that digestion is taking place – a phenomenon thought to be onomatopoeically named 'borborygmi' by the ancient Greeks, and explored further in the gruesome 19th century experiments of surgeon William Beaumont.</p><p>However, tuning in to the gut’s sounds can tell us more than whether we need a snack. Family doctor Margaret McCartney takes us through the process of how and why she and her medical colleagues may use a stethoscope to listen to your abdomen for both particular noises and silence.</p><p>Microbiologist Barry Marshall has taken medical listening one step further in his Noisy Guts Project. Inspired by microphones used to listen for termites hiding in walls, the Nobel Prize-winning scientist is trialling an acoustic belt, which could be worn to help diagnose and treat Irritable Bowel Syndrome.</p><p>Presenters: Hannah Fry, Adam Rutherford Producer: Jen Whyntie</p>