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Interviewer: Charlotte Stoddart
Hello and welcome to this week’s show in which we feature a researcher who’s working to understand slow landslides.
Interviewer: Adam Levy
Plus we’ll find out what worms can teach us about the wriggly problem of reproducibility. This is the Nature Podcastfor August the 24th2017. I’m Adam Levy.
Interviewer: Charlotte Stoddart
And I’m Charlotte Stoddart.
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Interviewer: Adam Levy
Landslides can devastate communities and claim lives. The ground itself becomes mobile, carrying with it huge amounts of potentially destructive energy. But the image you probably have in your head of huge chunks of land collapsing into houses and roads isn’t what landslides always look like. There are also landslides known as slow landslides. Slow landslides are landslides…
Interviewee: William Schulz
That a human can walk away from without fear of being overcome by the slide.
Interviewer: Adam Levy
This is William Schulz who’s a researcher with the US geological survey Landslides Hazards Programme in Denver, Colorado. Slow landslides may not sound like much cause for concern. After all, their maximum speed just a couple of metres per year. But they can cause serious damage and be hard to detect. What’s more, slow landslides don’t always stay slow. In fact, William explained to me that all landslides start off slow, whether or not we spot that part of their evolution.
Interviewee: William Schulz
In 1994, there was a landslide observed above this community of several hundred people in coastal California that was moving quite slowly, as in less than inches per week. During the subsequent winter rainy season, that landslide accelerated catastrophically and destroyed multiple homes. Luckily that slow movement had been observed so people were evacuated before that happened and that observation was because a road crossed landslide area. Unfortunately, in 2005, a landslide occurred in the exact same location and killed 10 people. In this case, no slow movement was observed leading up to it because it was no longer a road crossing – it was a natural hillside so no-one essentially was really paying attention.
Interviewer: Adam Levy
It’s tragedies like this that researchers like William hope to avoid in the future. This week, Natureis running a feature that looks in-depth at slow landslide research. And so, I spoke with William to find out what the work is like. He told me that studying landslide isn’t exactly like lab work.
Interviewee: William Schulz
I’ve oftentimes been inside landslides as well, gone down holes in landslides that have been bored. In landslides is one way that geologists will study the internal mechanisms of landslides and that can be quite disconcerting, especially when the landslide is actively moving. So that can be quite frightening.
Interviewer: Adam Levy
Going inside a landslide seems like a terrible idea.
Interviewee: William Schulz
Yes, doesn’t it.
Interviewer: Adam Levy
What work is particularly on the way right now to try and understand slow landslides better?
Interviewee: William Schulz
So a lot of research is directed towards better understanding characteristics of faults: what controls the faults of strength, because strengths of earth materials are very complex and change through time and change under different conditions and if I can understand why the faults on this landslide strengthen or something, then in that same sort of material on the other side of the planet, we can say, well this material will probably strengthen when a landslide occurs and therefore the landslide is likely to move slowly.
Interviewer: Adam Levy
What kind of advances in how we measure landslides have taken place over the last few years, few decades?
Interviewee: William Schulz
There have been a great deal of advances, first for measurements we can make on and in a landslide. We have very, very inexpensive sensors and field computers. However, remote sensing, or data that’s obtained remotely, rather than going on to the landslide itself is also a very significant advance that we’ve seen in the last few decades: whether it’s radar from space or the ground or an aeroplane or laser distance measurements, things of that nature. To better understand landslides and compare data we’ve obtained multiple times from these remote methods and understand how the landscape is changing.
Interviewer: Adam Levy
It sounds like there are so many factors that influence how a landslide accelerates or evolves. Is it something that we are now able to predict to some extent or is there still a lot of guess work?
Interviewee: William Schulz
To some extent but in very simplistic cases materials are so variable and since they can change significantly by adding or subtracting small components – a little bit of clay or a little more sand or something like that – can change behaviour dramatically and in ways that we can’t necessarily predict now. So we’re getting better at saying well, this much rainfall or this material will do this or that. We can drill holes in landslides and obtain the materials or we can go down in those holes and look at the materials and say well we’ve got great characterisation right there at that point. It can be dramatically different just a few metres away. We really need to make some advances there to be able to better forecast landslides.
Interviewer: Adam Levy
Working on this, does it still have an impact on you or does researching it mean that you’re more removed from the human consequences that these landslides can cause.
Interviewee: William Schulz
To me, those sorts of things never stop hitting home and reminding me why I’m in this business and to me what’s frankly to try and save people’s lives.
Interviewer: Adam Levy
That was William Schulz. For more on slow landslides, make sure to read the feature in this week’s Nature. Find it online at nature.com/news.
Interviewer: Charlotte Stoddart
Still to come later in the show, climate science in the US receives another blow from the government. And stars that blow up are more diverse than expected.
Interviewer: Adam Levy
But now for a quick look at two new studies. It’s time for this week’s Research Higghlights.
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Interviewer: Charlotte Stoddart
Everyone who’s looked in the mirror knows that light can bounce off things but we’re less used to light bouncing off light. Particle physicists at the LHC were accelerating lead ions which makes them emit light. The aim of the experiment was to smash the ions into each other but sometimes they missed. This gave physicists a chance to watch light scattering off light instead. The researchers spotted a grand total of 13 possible lights scatters out of 4 billion collision attempts. This is the first time light has been seen doing this at high energies. Read that paper in Nature Physics.
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Interviewer: Charlotte Stoddart
Many birds migrate to wait out Europe’s cold winters in sunny Sub-Saharan Africa. To see how they find their way, researchers played a trick on some reed warblers in a town in Russia. They put them in an enclosure and watched which direction they tried to fly in: south west. Then the researchers faked the direction of the earth’s magnetic field, mimicking what it would be in Scotland. The birds now tried to fly south east, as if they were setting off from Scotland. The researchers concluded that the birds were using the position of the stars as well as the earth’s magnetic field to figure out their flight path. Not bad for a bird-brain. That paper’s in Current Biology.
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Interviewer: Adam Levy
Next, reporter Geoff Marsh has been finding out about three researchers who’ve been making strenuous efforts to reproduce each other’s results.
Interviewer: Geoff Marsh
Gordon Lithgow works at the Buck Institute for Ageing and spends lots of his time working with the tiny round worms called Caenorhabditis. You might have heard of one species of these worms called C. elegans.
Interviewee: Gordon Lithgow
The worms are fantastic because they are a simple animal that age and we believe they age just like humans age but they age very rapidly. So their ageing is such that they only live about fifteen to twenty days, for most of the worm species that we work with.
Interviewer: Geoff Marsh
They’re not much to look at. They’re basically see-through and grow to about a millimetre in length. But because of their very short lifespans, experiments covering their whole lives can be done and dusted in under a month.
Interviewee: Gordon Lithgow
And it was also the first organism that genes were discovered that determined lifespan, so back in the late 80s, Tom Johnston discovered a mutation, a gene that he called Age 1 which increased the lifespan by 70% and that was really a dramatic discovery that changed the way that we think about ageing.
Interviewer: Geoff Marsh
So if genes could lengthen lifespan presumably, Gordon and others thought, so could compounds and drugs.
Interviewee: Gordon Lithgow
So back in 2000 we published a paper in Science which was probably the first paper in a main stream journal suggesting that drug-like molecules could extend a lifespan of an animal. It got a lot of attention back then but unfortunately, some other scientists were unable to replicate that result and that got us interested in that whole idea that some experiments don’t replicate between labs and that’s obviously a deep concern and we still believe that those compounds were having an effect but we couldn’t explain to other scientists how to see that.
Interviewer: Geoff Marsh
There could be any number of reasons why something as complex as lifespan might vary from lab to lab and several experiments over the years were failing to have their results replicated. In an effort to strengthen the results of such ageing studies, in 2013, the National Institute of Ageing, a part of the National Institutes of Health, funded a project called the Caenorhabditis Intervention Testing Program. Its first aim was to test ageing interventions across a genetic range of worms. It was also decided that these experiments should be carried out across three different labs: Gordon Lithgow’s as you’ve just heard, and two other independent ageing researchers, Patrick Phillips and Monica Driscoll. Here’s Patrick.
Interviewee: Patrick Phillips
When we study lab organisms frequently we just study one genetic strain at a time and so what people are finding is when you move from one genetic background to another, sometimes the things that you found in one experiment don’t reproduce across another one because of genetic differences, and so our studies really intended to look for things and responses that are robust across these genetic backgrounds. Every experiment that we did was automatically reproduced simultaneously in three different labs and so that we could address both the influence of genetic background and all other possible sources of experimental error at the same time so that when we came out with a conclusion, we could be very, very confident that it was robust both to genetic background and the other possible sources of reproducibility which have been something of an issue in the field.
Interviewer: Geoff Marsh
So in an effort to isolate the effects of the genetic backgrounds of the worms, the three labs set to work standardising their protocols and tried to get all of their experiments working exactly the same. But it became clear very quickly that there were several sources of variation that they hadn’t counted on.
Interviewee: Patrick Phillips
You know, the three labs used different microscopes and some of the microscopes had hotter lights than the others. Perhaps the most ridiculous one way that when we first got the data and analysed it, I saw that in one lab the worms lived several days longer and it made no sense to me. What had we done wrong? It turned out that their lab was used to scoring age from the first day of adulthood and the other labs were using the day that the eggs were laid and so that is the first day of life. That was a very easy thing to fix but sort of ridiculous that even at that level we weren’t recording the data correctly according to what our understanding was just because different labs have different ways of thinking about it.
Interviewer: Geoff Marsh
Eventually, after many long phone calls and tele-conferences, the three different labs did manage to get their protocols aligned and as a result the worms’ lifespans began to match across the labs. Having eliminated all the experimental differences they could find, they started to hit upon some interesting biological insights. Here’s Gordon again.
Interviewee: Gordon Lithgow
Some strains of worms age in different modes like they seem to either have a short lived mode or a long lived mode, irrespective of the fact that we had standardised the protocols so there’s something out there that we don’t know about yet: the dark matter of ageing where any particular cohort can be in a long-lived mode or a short-lived mode. That was weird and interesting and something we didn’t have an explanation for.
Interviewer: Geoff Marsh
An important new insight into the weird world of worm biology… But now that the labs were all in sync they could also start to see some interesting things about how various compounds were affecting the worms’ lifespans.
Interviewee: Gordon Lithgow
We also found that some compounds were absolutely rock steady, robust, reproducible, worked in every case in every genetic background in all three labs. And then we found compounds that weren’t quite like that: they don’t work in certain genetic backgrounds or they were just hyper-variable. They seemed to give really variable results in a way that we can’t explain.
Interviewer: Geoff Marsh
There is an argument for leaving the variability between different labs working on ageing research in order to weed out the compounds that are robust enough to shine through different experiments with different protocols and reagents. But even if you did want to standardise everyone’s experiments perfectly, there is a limit to how well you can do that.
Interviewee: Gordon Lithgow
There really is only so much you can do. If you think about every single variable from the elevation you happen to be at on the earth or the lights in the lab and the quality of the light and the various temperatures that the experiments are experiencing. Biology’s kind of messy that way. It’s difficult to control absolutely everything.
Interviewer: Geoff Marsh
So what does all this mean? Should all the labs around the world be on the phone to each other, rigorously examining their protocols to be exactly in line with one another? Here’s Gordon with some final thoughts.
Interviewee: Gordon Lithgow
For me I realised that we weren’t reporting enough information on the kinds of experiments we were doing. We just simply weren’t writing enough information down on the conditions in which we undertook the experiments. And now we document everything we can think of and there are temperature probes beside every single agar plate that contain the worms and we’re constantly jotting things down. There’s just a level of detail that I think is required in order to then convey to other scientists what you’ve actually done.
Interviewer: Charlotte Stoddart
That was Gordon Lithgow and Patrick Phillips talking with reporter Geoff Marsh. Gordon and Patrick have written a Comment piece with the head of the third lab, Monica Driscoll. Give it a read at nature.com/news.
Interviewer: Adam Levy
Time now for this week’s News Chat and on the line from Washington DC we’ve got Nature’s Us Bureau Chief, Lauren Morello. Hi Lauren.
Interviewee: Lauren Morello
Hi Adam.
Interviewer: Adam Levy
Now, this past week, Trump has been, in a way, been reiterating his distance from climate science. What’s he up to now?
Interviewee: Lauren Morello
Over the weekend, news broke that the Trump administration has decided to disband an advisory committee that was trying to make sure that a big climate report that comes out every couple of years on the science of climate change but also projects how it’ll affect various aspects of life in the United States. So Trump told all the members of that committee that he wasn’t going to renew the charter of the committee which expired on August 20thso basically it just kind of disappeared overnight.
Interviewer: Adam Levy
How far back does the history of this committee go? How long’s it been about?
Interviewee: Lauren Morello
So it’s only two years old but the people who are on it say it’s been really useful and it’s really helped them take the findings of this periodic national climate assessment and apply them to real life and make sure that they’re prepared for the effects of climate change.
Interviewer: Adam Levy
So where does this leave the report now that this committee has been disbanded?
Interviewee: Lauren Morello
Scientists who have been working on this report, who are just waiting for it, have been worried that the Trump administration is basically going to meddle with its conclusions. There’s a report on the state of climate science that feeds into this bigger national report on the impacts of climate change and that science report has been undergoing a final review by political appointees at various science agencies and they were supposed to finish that review on August 18th. So the director of the programme that’s in charge of this report says everything’s still on track but I think people are kind of waiting with bated breath and the fact this advisory committee that has to do with the overall national climate assessment has been disbanded is making people a little nervous.
Interviewer: Adam Levy
What people are we talking about? Who’s actually waiting for this report? And who would use its findings?
Interviewee: Lauren Morello
The report has a wide variety of users. So first of all, people who are waiting for it include just the general climate science community, but various federal agencies use the conclusions of the report to help them with their planning like for example, under President Obama, the transportation department was taking likely effects of climate change over the next couple of decades and planning various transportation projects. The report’s also really designed to be useful to business and industry and then also to local and state governments. And when I say local and state governments it includes people who manage water supplies, who want to get a handle on how rain or snowfall patterns in their area might change and for businesses, for example, there are farmers or big agribusinesses who want to have an idea about how temperature and precipitation trends are going to change because that would affect their crops.
Interviewer: Adam Levy
And getting rid of this committee isn’t a stand-alone event. How does it fit into other moves from the Trump administration on science and the environment?
Interviewee: Lauren Morello
I think overall it’s fair to say at this point that the administration has let a lot of science jobs just wither by attrition. They’re not filling various posts. Trump doesn’t have a science advisor. The science division of the office of science and technology policy at the White House has been basically empty for a while now. And then also the administration is moving to disband some advisory committees and then finally you see some appointments to various government science posts that practising scientists, I think, find questionable. For example, the Trump administration just named somebody to be the top scientist at the department of agriculture who’s actually not a scientist at all – has no scientific training.
Interviewer: Adam Levy
Let’s take a break from these science dramas on earth and look further out into space. There’s news of type 1a supernovas and scientists may have somehow misjudged them. Before that, what actually is a type 1a supernova and why do they matter?
Interviewee: Lauren Morello
Okay, so supernova is just a fancy name for exploding star and type 1a supernova are just a variety or a flavour of those exploding stars. The reason that they matter is that scientists have found that this particular type of supernova is really consistently bright. They call them standard candles and basically because these things are so bright, they act like cosmic mileposts. Scientists can measure distances in space relative to these supernova, so these cosmic mileposts were used to prove that the universe is expanding at an ever increasing rate which in turn seems to confirm the idea that there’s tonnes of dark energy in the universe and altogether those discoveries won the noble prize in 2011. So these things are a big deal.
Interviewer: Adam Levy
How standard were they actually thought to be? Did we think they were all basically identical?
Interviewee: Lauren Morello
The writer of our news story, I think, put it in a really nice way: that astronomers basically thought these things came off a cosmic assembly line, that they form the same way and they were pretty uniformly bright. But over the past couple of years people have started to doubt this.
Interviewer: Adam Levy
And what’s the latest on this? Is there a new paper out?
Interviewee: Lauren Morello
There’s a paper on the archive pre-print server that contains evidence that these supernova are formed at least two different ways. So this is a theory that’s been floating around for the last couple of years. People have theorised that you can get these supernovae to form either by having two white dwarf stars merge, or you can have a white dwarf that starts pulling material off a bigger companion star and the white dwarf becomes so dense that then it explodes. So, scientists had only seen evidence of the first type – the two white dwarfs merging. Basically the two white dwarfs completely obliterate each other and they don’t leave much mess behind – just a supernova and no extra material really. But now they’ve seen evidence of the second type of supernova which is when the white dwarf pulls material off the companion star and then explodes. So that leaves a whole bunch of evidence behind. The companion star survives the explosion and then material ejected from the supernova hits that companion star and it lights up. So that’s what they’ve seen. So now there’s finally some observational evidence that there’s a second way to make one of these things.
Interviewer: Adam Levy
So now that we know that these so-called standard candles aren’t as uniform as we thought, does that call into question these results that we had before, you know, that the universe is expanding at an accelerating rate?
Interviewee: Lauren Morello
Nobody told us that it calls into question those results. Scientists have found a way to compensate for small variations in brightness between standard candles but what they said was now that they know this they can develop better corrections and the results can be more precise.
Interviewer: Adam Levy
Thanks for joining us Lauren. Make sure to check out all the latest science news at nature.com/news, or at @NatureNews on Twitter.
Interviewer: Charlotte Stoddart
That’s all for this week but in case you were hoping for some eclipse coverage, don’t miss our video all about the lessons eclipses have taught us over the centuries. That’s at youtube.com/NatureVideoChannel. You’ll also spot a brand new animation there looking at possible new treatments for critical limb ischaemia, a serious circulation condition.
Interviewer: Adam Levy
No show next week as the summer holidays draw to a close. But we’ll be back on your podcast feeds on the 7thof September. Until then, I’m Adam Levy.
Interviewer: Charlotte Stoddart
And I’m Charlotte Stoddart.
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