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THE POWER

OF FASTING

Why an empty plate may hold the secret to

a longer life

EARLIEST ANIMALUnusual fossil reveals

surprising origins

TWO EGGS, ONE BABYSame-sex mice reproduce.

Are we next?

SPACECRAFT CRASHSoyuz emergency

spells trouble for ISS

LUCY HAWKINGOn her father’s extraordinary legacy

PLUS 400-TONNE FUNGUS/ MOONMOONS /BACKWARDS CHEMISTRY

WEEKLY October 20– 26, 2018

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20 October 2018 | NewScientist | 1

CONTENTSnewscientist.com/issue/3200

Leaders

3 We must ensure that data-driven medicine puts patients first. The joy of moonmoons

News

4 THIS WEEK Adapting to a warmer world. Photography prize for monkeys. Rabbit virus hits hares? UK to put folic acid in flour

6 NEWS & TECHNOLOGY

Smacking linked to teen violence. Placental stem cells help hips heal. Electric chewing gum keeps its flavour. Space rocks could seed life through the galaxy. Earliest ever animal fossil. Mysterious cosmic radio burst near Earth. Hospital of the future. Moons can have moons. Mice with two biological mothers. 400-tonne fungus. A laser that shouts. Forensics gets a genetic upgrade

17 IN BRIEF Jiggling pills end constipation. We remember 5000 faces. Bees fall silent in eclipse. AI’s weird limbs. Sneaky T. rex

Analysis

22 INSIGHT Why trying to end all suicide could be a bad idea

24 COMMENT More help needed for those who lose a pregnancy. Medical cannabis in limbo

25 ANALYSIS Crisis in space leaves the ISS inaccessible

Features

30 The fashion for fasting

Why an empty plate may hold the secret to a longer life

34 Full steam ahead

Cracking the immense promise of geothermal power

38 The disassembly line

How to make molecules at the touch of a button

42 Memories of my father

As Stephen Hawking’s final book is published, his daughter Lucy reflects on his legacy. Plus an exclusive extract from the book and a review

Culture

46 Red sky at night A deeply realised novel from Kim Stanley Robinson peeks into our possible future on the moon. PLUS: This week’s cultural picks

Regulars

26 APERTURE

The world’s most extraordinary freshwater environments

52 LETTERS

For mammals, matriarchy is second nature

55 OLD SCIENTIST

50 years ago56 FEEDBACK

Goats with a strange thirst57 THE LAST WORD

Waxing miracle

On the cover

25 Spacecraft crash

Soyuz emergency spells trouble for ISS

13 Two eggs, one baby

Same-sex mice reproduce. Are we next?

8 Earliest animal

Unusual fossil reveals surprising origins

30 The power of fasting

Why an empty plate may hold the secret to a longer life

42 Lucy Hawking

On her father’s extraordinary legacy

400-tonne fungus (13). Moonmoons (3 and 10). Backwards chemistry (38)

This week Time to adapt to a warming world 5Volume 240 No 3200

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Plus

ManagementExecutive chairman Bernard GrayChief executive Nina WrightFinance director Jenni PrinceChief technology officer Chris CorderoyMarketing director Jo AdamsHuman resources Shirley Spencer Non-executive director Louise Rogers

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LEADERS


ADVANCES in technology have done wonders for keeping us alive and healthy – think where we would be without the likes of MRI machines, heart monitors or ventilators. So it is heartening to see that Great Ormond Street Hospital in London is now experimenting with how the latest advances in artificial intelligence, robots and face recognition might aid patient care (see page 10).

Unlike medical tech of old, this latest generation heavily relies on the use of data. And as we are increasingly learning, data collected for one reason often ends up being used for another.

For example, people who signed up to DNA ancestry services probably never expected their genetic data to be put to work solving murders. Now, thanks to the rapid pace of genetic technology, police are using it to do just that (see page 14).

Even if most people would be happy to assist with such enquiries, the benefits of other reuses of data are thornier still. Last week, it was revealed that Amazon has patented the ability of its Alexa voice assistant to detect when you are ill, such as by listening out for coughs and sniffles, then offer to buy cough drops. In the same vein, it is easy

to imagine that a face-recognition system designed to identify hospital visitors could one day be redeployed to search for signs of depression.

Although medical data is generally subject to strict safeguards, it is not clear whether data that later becomes medically useful can be equally protected. After all, you never know what might come in handy down the line. Good healthcare relies not just on the latest advances, but also on trust. In striving for innovation, medical practitioners must do their best to protect their patients – both now and for the future. ■

Patients before techWe must ensure that data-driven medicine puts people first

LAST week, New Scientist sent certain corners of the internet into rapturous delight by publishing a story about the potential for moons to have moons of their own (see page 10). This included a suggested name for such objects: moonmoons.

The response on social media was an immediate outpouring of glee. Something about the word’s

childlike simplicity makes it a pleasure to say, and thousands of readers were quickly firing off their own reactions. As it happens, “Moon Moon” is the name of a five-year-old meme depicting a wolf looking stupid, which certainly helped the idea spread.

Some astronomers are bemoaning the use of moonmoon, suggesting it

makes light of a serious field of study. But given that terms such as super-Earth, twotino and cubewano are all an accepted part of the literature, moonmoon doesn’t seem a huge departure.

Ultimately, it remains to be seen whether the word sticks or gives way to more po-faced alternatives such as submoon or second-order moon. But to lose moonmoon, and the joy it brings, would seem an astronomical shame. ■

The joy of moonmoons

EditorialEditor Emily WilsonManaging editor Rowan HooperArt editor Craig Mackie

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Reporters (UK) Jessica Hamzelou Michael Le Page, Clare Wilson, Sam Wong (US) Leah Crane, Chelsea Whyte (Aus) Alice Klein

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4 | NewScientist | 20 October 2018

THIS WEEK

TECH giant Apple has strongly

criticised a proposed Australian

law that would force companies to

provide access to encrypted data.

“Criminals and terrorists… may

start their attacks by accessing just

one person’s smartphone,” said

Apple in a letter to the Australian

government. “In the face of these

threats, this is no time to weaken

encryption.”

The proposed bill’s public hearing

is on 19 October, but Australia is not

the first to attempt a clampdown

on encryption. Law enforcement

agencies and politicians around the

world have long been calling for such

measures, claiming it is essential to

fight crime and terrorism. The UK’s

prime minister, Theresa May, has

repeatedly pressed the need for a

ban on encryption.

Computer scientists say there is

no way to create “back doors” for law

enforcement without making devices

more vulnerable to hackers, such as

those who break into systems and

demand a ransom to restore them.

GOVERNMENT ministers are backing

a plan to fortify flour with folic acid

in the UK, according to The Guardian.

The move is intended to help

reduce birth defects that affect the

brain and spine. A lack of folic acid

can lead to problems with neural tube

development, resulting in conditions

such as spina bifida and anencephaly.

Pregnant women and those trying

to conceive are currently encouraged

to take a daily supplement of

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400 micrograms of folic acid.

But many don’t take

supplements. “Many pregnancies

are not planned, meaning many

women will not have taken folic

acid around the time of conception

and very early in their pregnancy,”

says Clare Livingstone from the

Royal College of Midwives.

Flour is already fortified with

vitamins and minerals in more

than 80 countries, including the

US, Canada and Australia. When

fortification was introduced in

Canada in the 1990s, a marked

decrease in birth defects was seen.

BROWN hares are turning up dead

across the UK, leading to fears that

the highly infectious rabbit disease

myxomatosis has jumped species.

Myxomatosis, caused by the

myxoma virus, was introduced to

rabbits in Australia and Europe in the

1950s to reduce their numbers. The

disease tore through populations,

killing 99 per cent of rabbits in the UK.

Numbers bounced back after rabbits

developed some resistance, but the

disease is still prevalent.

Now the University of East Anglia

and the Suffolk and Norfolk wildlife

trusts are warning that a mutated

form of the virus may be infecting

hares. There have been reports

before of the disease seeming to

affect hares, but now a large number

of dead hares have been found over

a short period of time in the UK – in

one case six in a single field.

If the disease were to hit hares as

hard as it did rabbits, the effect could

be devastating. UK hare populations

are already thought to have declined

by 80 per cent over the past century.

Concern over hare deaths

Plan to add folic acid to UK flour

Apple hits back at anti-encryption law

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Golden duo grab prize

A PORTRAIT of two golden

snub-nosed monkeys has won

the 2018 Wildlife Photographer

of the Year competition.

The pair were snapped by

Dutch photographer Marsel van

Oosten in the temperate forest

of China’s Qinling mountains, the

only place where this endangered

species lives.

“This image is a symbolic

reminder of the beauty of nature

and how impoverished we are

becoming as nature is diminished,”

says Roz Kidman Cox, a member

of the judging panel.

The photography competition

is produced by the Natural History

Museum in London.



For new stories every day, visit newscientist.com/news

IT IS not enough to try to limit further global warming – we must also do far more to ensure we survive it. That’s the message from a coalition of global figures, including former UN head Ban Ki-moon and billionaire Bill Gates.

They are part of the Global Commission on Adaptation launched this week, which says that the impact of global warming is being felt much sooner and more powerfully than expected. To keep reducing global poverty and maintain economic growth, it says societies must do much more, much faster, to adapt.

“Adaptation action is not only the right action, it is the smart thing. We need to make this case more aggressively. The costs of adapting are less than the cost of business as usual. And the benefits many times larger,” says Ban, who, with Gates,

is one of 28 commissioners heading the new initiative.

Climate adaptation is not just about special projects, says Kristalina Georgieva, CEO of the World Bank and another of the commissioners. Everyone should think about resilience to climate change when making decisions: from governments and business leaders to the general public, for instance when buying a home.

“A very significant opportunity for adaptation comes from mainstreaming resilience in the normal investments we make,” says Georgieva. “It doesn’t have to be a more expensive investment, it has to be done with risk in mind.” For example, she describes how some farmers in Bangladesh

have switched to raising ducks instead of chickens. In a flood, chickens drown but ducks swim.

Bangladesh has also succeeded in greatly reducing deaths from cyclones by improving warning systems and building shelters. In 1970, half a million people died in one such storm; in 2007, fewer than 5000 perished in a cyclone.

Adaptation is especially crucial for the poorest, because they are hit hardest. Climate change may plunge around 100 million people back into extreme poverty by 2030. “The urgency around adaptation cannot be overstated,” says Patrick Verkooijen, CEO of the Global Centre on Adaptation initiative. He will help to run the new commission.

All those involved in the call for adaptation still stress the need to cut emissions to limit, or mitigate, further warming. “We are the last generation that can mitigate climate change effectively. We are the first generation that has to live with its consequences,” says Georgieva. “That leads to a very obvious

conclusion: we have to mitigate and adapt at the same time.”

The launch of such a big adaptation initiative just a week after a major UN report on what it would take to limit warming to 1.5°C might be seen by some as an admission of defeat. But scientists have always made it clear that we need to adapt even if warming is limited to 1.5°C or 2°C by 2100. Based on current policies we are heading for more than 3°C.

Not defeated

“For quite some time there has been a sense that if we opt to adapt, that means we’re accepting defeat in the fight against climate change,” says Georgieva. “But the truth here is that we already are experiencing the consequences of the changing climate. It’s not defeat, it’s reality that we face.”

That means giving equal priority to adaptation. Half of the money the World Bank lends for climate-related projects – $20.5 billion in the past year – now goes on adaptation, she says.

The commissioners also say we can combine adaptation with efforts to limit climate change. For instance, solar panels keep homes supplied with electricity if a disaster damages power lines.

While the commission paints a rosy picture of the benefits of adaptation, in reality there will be hard choices, such as whether to retreat from low-lying coastal areas or build flood defences. This will be true even for wealthy cities such as New York.

“Some places, like lower Manhattan, will clearly be defended with walls and other structures. But will billions be spent to protect, say, Howard Beach, a low-lying neighbourhood in Queens? I don’t think so,” says Jeff Goodell, author of The Water Will Come. “In most places, retreat is inevitable. And it will be driven by simple economics. The hard truth is, adaptation to quickly rising seas is a luxury that few can afford.” ■

Time to adapt to a warming worldClimate change is hitting faster than expected, says Michael Le Page

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Growing flood risks are one impact

of the rise in global temperature

“We are the first generation that has to live with the consequences of climate change”



NEWS & TECHNOLOGY

Clare Wilson

A GLOBAL survey has found that teenagers get into more fights in countries where it is legal to spank children, prompting campaigners to renew calls to make corporal punishment illegal.

Smacking children used to be commonplace in parenting, but a growing list of countries have banned it, including Sweden, Germany and New Zealand. The practice will soon become illegal in Scotland, and there are calls for the same to happen throughout the rest of the UK.

Supporters of smacking say that it can be necessary for discipline, but campaigners say that it makes parental child abuse more likely, and promotes violence more generally. To see if childhood smacking might later affect teenage behaviour, Frank Elgar of McGill University in Montreal, Canada, and his colleagues analysed child survey data from 88 countries.

These countries were each classed in one of three ways: no smacking bans, full smacking bans, or partial smacking bans, where smacking isn’t allowed in

schools, but is legal for parents, as is currently the case in the UK.

The analysis found that 13-year-olds from places with full smacking bans were less likely to get into frequent fights than those from nations where it is allowed everywhere. In boys, who fought the most, the rates for frequent fighting were 8.5 per cent where there are full smacking bans and

12 per cent where there are none (BMJ Open, DOI: 10.1136/bmjopen-2018-021616 ).

This suggests “bans not only keep children safe from adults, but also from their peers”, says Alana Ryan of the UK’s National Society for the Prevention of Cruelty to Children, which has long campaigned for a ban on smacking in the home.

But Catey Bunce of the UK Royal Statistical Society says this makes the mistake of assuming that a correlation between two things

means one causes the second. It could be that the second causes the first. For instance, teenagers who get into lots of fights might grow up to be tougher disciplinarians.

Or perhaps smacking and teenage fights are both affected by a third factor, such as broader societal attitudes. For centuries, there has been a slow decline in violence across many aspects of society, according to an idea popularised by Steven Pinker of Harvard University. Any falls in smacking and teenage fighting could be two manifestations of this trend, without one directly causing the other.

“As a parent, I would not smack my children, so it is tempting to believe if they were exposed to it they would become more aggressive,” says Bunce. “But you need to be wary of jumping from correlation to causation.”

Another caveat to the latest findings is that there was just a small difference in frequent fighting between countries with full bans and partial bans. In boys, the rates were 8.5 per cent versus 10 per cent, a gap too small to be found statistically meaningful by this analysis.

But Elgar says other evidence shows that smacking makes children more violent. “Being hit or spanked or slapped does affect how kids react in their own social relationships,” he says. ■

Smacking linked to teenage violence

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“ Six months after the operation, people who got stem cell doses had stronger hip muscles”

STEM cells taken from placentas

have healing properties that can

help people recover from having

their hip joint replaced.

Placentas are normally thrown

away after childbirth, but now

Israeli company Pluristem has taken

discarded placentas and developed

a batch of mesenchymal stem cells

from them. These cells have the

Stem cells from placentas could help fix muscles

potential to turn into different kinds

of tissue and release chemicals that

promote healing.

To see how the cells affect muscle

repair, Tobias Winkler of Charité –

Berlin University of Medicine in

Germany and his colleagues tested

two different doses of the cells in

20 people having hip replacements.

During the operation, surgeons have

to cut into muscle tissue around the

joint, which can leave people limping

for several months, particularly if it

isn’t their first hip replacement.

Six months after surgery, people

who got a dose of cells had stronger

hip muscles than those in the

placebo group, as measured by

an exercise machine (Journal of

Cachexia, Sarcopenia and Muscle,

doi.org/cvsw). All of the people in

the experiment – even those in the

placebo group – were limp-free by

the time they were tested at six

months, probably because everyone

was having their first hip surgery,

says Winkler.

The improvements seen in strength

suggest that the cells would reduce

limping in people having second or

third joint replacements, where the

muscle starts off in worse condition,

says Winkler.

Dennis McGonagle at the University

of Leeds, UK, says animal studies

show that stem cells are often killed

by the recipient’s immune system

when they are injected into the body.

But mesenchymal stem cells seem to

release tiny packages of beneficial

compounds before this happens.

“They are full of growth factors and

other goodies,” he says. Clare Wilson ■

Teenagers seem to fight more

where spanking is permitted–



LIFE finds a way – perhaps even across the stars. It may really be possible for organisms to travel all over the galaxy by hitching a ride on a fast-moving rock in a phenomenon called galactic panspermia. In this way, just a few inhabited worlds could spread life throughout the Milky Way.

In October 2017, astronomers spotted the first interstellar object we have ever seen come through our solar system, called ‘Oumuamua. That was the first concrete proof that rocks can be tossed out of orbit from distant stellar systems and make it intact to our solar system.

Of course, it is not enough for a space rock to travel between the stars. In order to transfer life, it must also be captured by a star’s gravity and eventually smash into a planet.

Now, Idan Ginsburg, Manasvi Lingam and Avi Loeb at Harvard University have calculated just how often these banished rocks might be captured by a new stellar system, and how likely any life

stuck on such interstellar projectiles would be to survive.

“It’s like billiards,” says Ginsburg. “You hit the cue ball and it hits the other balls, and beside just transferring momentum it also spreads life, and then life spreads across the whole table, which is the galaxy.”

The team has found that up to 100 million life-bearing objects with a radius of 200 kilometres – about half the size of Saturn’s moon Enceladus – could have been captured in stellar systems around the Milky Way.

Even about 1000 Earth-sized objects could have been collared in this way, they say (arxiv. org/abs/1810.04307v1).

Smaller objects are much more likely to make the journey between stars, but the smaller they get, the harder it is for

microbes to take shelter from the punishing space environment in the interior of the rock.

“It’s a very dangerous ride, but you can think of the microbes as tiny astronauts sitting in a natural spacecraft,” says Loeb. “I would actually be thrilled to be a microbe sitting in a rock that makes it across the Milky Way.”

Once one of these life-laden rocks is captured into orbit around a new star, it can smash into a planet, dropping off its passengers. The same process on a smaller scale could also spread life to other planets in the system.

Many Mars rocks have been blown off the planet by impacts, ending up on Earth. This has led some people to speculate that life on our planet could have come from Mars. It is even possible, if unlikely, that life on Earth began with interstellar microbes, says Loeb.

However, Ed Turner at Princeton University says the team may have overestimated the likelihood that these captured objects carry life. And many of these objects would not be chipped from larger, habitable planetary bodies, so if they have life, it must have evolved there on its own.

“Only a tiny fraction of the objects that would be captured would plausibly carry life,” he says. “If that somehow were not the case and a lot of them carried life, then life is very common and you probably don’t need panspermia anyway.”

Our space-faring descendants may even be able to test this idea. If life in different places around the galaxy is varied and diverse, that would be an indication that it arose independently on each world. However, if there are groups of stellar systems with similar life on their planets, this could mean that microbes really are travelling between the stars, says Loeb. Clare Wilson ■

CHEWING gum that zaps your tongue

with electricity keeps the flavour

going forever.

The pain-free device is called

“unlimited electric gum”. It uses the

piezoelectric effect – a phenomenon

where some materials produce

electric charge when squeezed. When

the “gum” is chewed, it produces a

small current, which tricks the tongue

into experiencing different tastes.

It currently produces a salty or

bitter taste. But the hope is to extend

that, since other research has shown

that, by varying the pattern and

strength of electric charge, it is

possible to induce all five of the basic

tastes our mouths pick up: bitter,

salty, sour, sweet and umami.

At an event in Japan earlier this

year, 80 people tried the gum. Almost

everyone reported experiencing salty

or bitter tastes. Some said chewing it

was a bit like chewing niboshi, which

are small dried infant sardines used in

snacks and seasonings in Japan.

The gum consists of a piezoelectric

element and electrodes, wrapped

in a thin plastic film. It is a couple of

centimetres wide, like a standard

stick of gum. Unlike real chewing gum,

the electric version will continue to

stimulate the taste buds for as long

as it is chewed – and it won’t break

down into a sticky glob.

Naoshi Ooba at Meiji University in

Japan and his colleagues created the

device, and demonstrated it at the

ACM Symposium on User Interface

Software and Technology in Berlin,

Germany, this week.

This is the latest in a line of

taste-related gadgets devised by

researchers. These include a digital

lollipop that people can lick to get

different tastes, and a virtual

lemonade that uses electrodes to trick

someone into thinking that water is

actually the fruit-flavoured drink.

Ooba and his team plan to add other

flavours to the electric gum, and want

to eventually create a product that

people can buy. Timothy Revell ■

Alien life could ride space rocks to travel the stars

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For daily news stories, visit newscientist.com/news

“ I would actually be thrilled to be a microbe sitting in a rock that makes it across the Milky Way”

Hi-tech chewing gum will never lose its flavour

Panspermia is the idea that

asteroids seed life through space



NEWS & TECHNOLOGY

Chelsea Whyte

SPONGES were probably one of the earliest animal groups to evolve, but it has proved hard to work out exactly when in geological time they appeared.

Now, an analysis of ancient rocks and oils has turned up traces of steroids made by early sponges that indicate they may have been populating the ancient sea floor at least 120 million years earlier than we thought.

“If animals first appeared in a predominantly bacterial or microbial world, they would need to harness microbes and live symbiotically with them,” says Gordon Love at the University of California, Riverside. That may be why sponges produce a vast array of sterols: steroids with antibacterial properties that could let them harbour microbes without harm.

The earliest sponges belong to a class called demosponges, which produce sterols that can be preserved in rocks as characteristic sterane molecules. Love and his team went hunting for these “molecular fossils” in rock and oil samples from Oman,

Siberia and India that date to between 635 and 660 million years ago.

They found plenty of a sterane called 26-methylstigmastane that, as far as we know, is only produced by demosponges.

In previous work, Love had found another possible sponge biomarker, called 24-isopropylcholestane (24-ipc), in the same rocks. But some modern algae make a similar compound, so the ancient 24-ipc might not have come from sponges. Love says the evidence for sponges in the rocks is now clearer (Nature Ecology & Evolution, doi. org/ cvsx).

But the finding hints at a big puzzle. Sponges have “skeletons” made of silicon fibres called spicules that give structure to their holey bodies. We don’t see fossil evidence of spicules until about 540 million years ago, at the dawn of the Cambrian period.

“If the biomarkers here are a genuine sign of sponges, then we’ve got a huge problem with the fossil record,” says Joe Botting at the National Museum Wales, UK.

It could be that older spicules are out there and we just haven’t

discovered them yet. But Botting says there are many people hunting for them – and they have yet to find any.

So perhaps some other organism was making these compounds 660 million years ago, having evolved the same ability independently of sponges. Although we know that, today, sponges produce more sterols than all other complex life forms combined, and we haven’t found

other living organisms that make the specific molecules that Love’s team found, there is a chance they are – or once were – out there.

Love says there is another possibility: the very first sponges may have lacked silicon spicules that would have been preserved as microfossils. If so, this would explain why there are molecular signs that sponges were present 660 million years ago even though there is no microfossil evidence. In other words, we could be looking for fossils that don’t exist. ■

Earliest signs of animal life found

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“The team’s telescopes are trained on the galaxy to try to pinpoint the source of the fast radio bursts”

A STRANGE flash of radio waves

detected from space has been traced

to a galaxy that lies relatively nearby.

Fast radio bursts (FRBs) are blasts

of radio waves that last for only a few

milliseconds yet can contain as much

energy as our sun puts out in decades.

More than 50 have been spotted since

they were first discovered in 2007, but

we still don’t know what causes them.

Cosmic radio signal spotted close to Earth

Most detected bursts have been

from billions of light years away,

making them hard to study. But Ryan

Shannon at Swinburne University

of Technology in Australia and his

colleagues recently found one that

occurred unusually close to Earth.

Dubbed FRB 171020, it was spotted

by the Australian Square Kilometre

Array Pathfinder telescope. Elizabeth

Mahony at Australia’s national science

institute, CSIRO, and her colleagues,

including Shannon, have now

determined that it probably came

from ESO 601-G036, a galaxy that is

120 million light years from Earth

(arxiv.org/abs/1810.04354v1).

The galaxy is of a comparable size

and has a similar star formation rate

and oxygen abundance to the only

other galaxy in which an FRB has been

pinpointed, which lies 2.4 billion light

years away from us in the constellation

Auriga. However, ESO 601-G036

doesn’t emit the same continuous

stream of low-level radio emissions

as the Auriga galaxy, contradicting

previous suggestions that such

emissions are required for FRBs.

Mahony and her team are now

focusing their telescopes on ESO

601-G036 to confirm that it does

produce FRBs. If they spot another,

they may be able to pinpoint which

part of the galaxy it comes from.

“Then we might actually be able to

solve the mystery of what causes

these fast radio bursts,” she says.

Some people believe they are alien

messages, but Mahony says they

are more likely to be the products of

astrophysical events, like the creation

of neutron stars. Alice Klein ■

There is a big puzzle over

when sponges evolved


AVAILABLE NOWnewscientist.com/books

WHAT IF DINOSAURS

STILL RULED THE EARTH?

WHAT

IF THE

RUSSIANS

GOT TO

THE MOON

FIRST?

WHAT IF TIME STARTED

FLOWING BACKWARDS?



NEWS & TECHNOLOGY

STARS are orbited by planets, which

are orbited by moons, but what

comes next? More moons, according

to a new analysis.

A moon of a moon has no formal

name, perhaps because we have

never spotted one, but both submoon

and moonmoon have been suggested.

Such an object would have to be close

enough to its host moon to remain

gravitationally bound to the moon

instead of the larger planet, but not

so close that the moon would rip it

apart or pull it out of orbit.

Juna Kollmeier at the Carnegie

Observatories in California and

Sean Raymond at the University of

Bordeaux, France, have calculated

that four moons in our solar system

could theoretically have submoons:

Earth’s moon, Jupiter’s moon Callisto

and Saturn’s moons Titan and Iapetus

(arxiv.org/abs/1810.03304).

These moons are all relatively large

and far from their planets, so there is a

small area in orbit around each where

the planet’s gravity might not steal

a moonmoon away. But even if these

moons could host a moonmoon, it

would be difficult to get one in the

right place, says Raymond.

“Something has to kick a rock into

orbit at the right speed that it would

go into orbit around a moon, and not

the planet or the star,” he says. And

if that moon moved around over the

course of its evolution, as our moon

has, it is unlikely the submoon would

stick around.

There has also been speculation

about whether a moonmoon could

orbit a distant moon that may be

the first ever spotted outside our

solar system, around a planet called

Kepler-1625b. That exomoon, if it

exists, is probably a gas giant, orbiting

an even larger gas giant.

“This system where you’ve got a

giant planet and a Neptune-sized

moon that’s kind of far away from the

planet is sort of the best-case scenario

for a moonmoon,” says Raymond.

Leah Crane ■

Moons of a moon are called moonmoons

Douglas Heaven

IN THE five steps from the door to the reception desk, my photo has been taken, my face saved in the system and an ID number assigned. For the rest of my time at this new high-tech unit in Great Ormond Street Hospital (GOSH) in London, I am followed by an AI.

Video screens that will be visible only to staff show my head in a red box, annotated with a score showing how confident the computer is that I am who it thinks I am.

Tracking systems like this are just one of the technologies being tested at GOSH’s DRIVE (Digital, Research, Informatics and Virtual Environments) unit, which opened last week. The unit is a collaboration between the UK’s National Health Service, University College London and several tech companies, including Microsoft, Samsung and UK chip-maker Arm.

Although the unit is part of GOSH, it doesn’t provide clinical care. Instead, it is a place where

engineers can interact with patients, doctors and nurses – sometimes role playing actual scenarios – to find out what new tech can and can’t do before it is rolled out in clinical settings across the NHS.

“It’s a digital sandpit,” says Noel Hurley at Arm. “It lets us experiment and play and build and break things in a safe environment.”

Arm’s chips power most of the world’s smartphones, but it is also involved in healthcare, providing the hardware for many

medical devices. The company now wants to embed AI in those devices so they can make quick, automated decisions.

Medical AI has made great strides in diagnosing certain conditions, such as cancer and eye disease. But Arm is more interested in the smaller tasks.

By streamlining the simple actions that are performed in hospitals thousands of times a day, such as registering patients and tracking people’s movements, it hopes to free up more staff time for patient care.

Since GOSH is a children’s hospital, there will be a focus on how tech can improve the care of younger people. Several projects are under way, including a blue whale in the main entrance and rabbits hopping about the wards – visible only to those with an augmented reality app.

One project already up and running is Project Fizzyo, which helps children with cystic fibrosis put up with their physiotherapy by making the physio device they have to squeeze into a game controller. The better you get at doing physio, the better you are at the game, says Neil Sebire, managing director at DRIVE.

Hospital staff are also asking young patients what they would like in a hospital. “Most of them want robots,” says Sebire. Two robots are now being developed that can tell stories inspired by nearby objects. “Children are not limited by what they think tech can do,” he says. ■

Futuristic hospital unit is launched

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“Projects under way include a blue whale that is visible only to those with an augmented reality app”

Robots, such as Sota, can assist

with health checks


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Humanity will need the equivalent of 2 Earths to support itself by 2030.

We spend 50% of ourlives daydreaming.

People lying down solve anagrams in

10% less timethan people standing up.

60% of us experience

‘inner speech’ where everyday thoughts take a back-and-forth

conversational style.

About 6 in 100 babies

(mostly boys) are born with an

extra nipple.

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NEWS & TECHNOLOGY

Michael Le Page

WE ARE a small step closer to the day when two women or two men could have biological children of their own, thanks to improved methods for creating mice with same-sex parents. But the work also shows that there is a huge amount still to do before this could be attempted in humans.

“It is [right] to emphasise the risks, and the importance of safety, before any human experiment is involved,” says Wei Li at the Chinese Academy of Sciences in Beijing, who led the latest research. “But we think our work does take it closer.”

The biggest obstacle to creating babies from same-sex parents is a genetic phenomenon called imprinting. This means certain genes in the sperm genome are switched off by adding epigenetic markers to the DNA. These are molecules that affect gene activity but don’t change the underlying DNA sequence. Imprinting also occurs in eggs, but with different genes turned off.

Normal imprinting in sperm and eggs is crucial for embryo development in mammals.

Even if you somehow combined the genomes of two females – or two males – in an egg and kick-started development, the imprinting would not be normal and the resulting embryo will die.

But in 2004, a group in Japan managed to create Kaguya the mouse, the first ever mammal

with two mothers. They achieved this by deleting a piece of DNA in one of the female genomes to try to mimic normal imprinting. But 500 attempts produced just two mice that survived to adulthood.

Li and his team have greatly raised the success rate by deleting three bits of DNA to better mimic the normal imprinting required for embryo development. They made a total of 200 attempts at creating a mouse with two

mothers, succeeding 27 times.What’s more, Li’s team also

created 12 mice with two fathers from 500 attempts, by deleting seven pieces of DNA to try to mimic imprinting. However, none survived to adulthood (Cell Stem Cell, doi.org/cvrw).

Li’s work reveals more about which imprinted genes are crucial for normal development in mice. However, it is not clear if the results apply to other mammals such as humans. The team will test this by trying to create monkeys with two mothers.

Before we could even think of trying to create human babies with same-sex parents, we would need a way of mimicking imprints without resorting to genetic modification, not least because permanently deleting genes would have harmful effects in later generations.

But that might just be possible. Several groups are modifying CRISPR gene-editing tools to allow them to add or remove epigenetic markers without changing the underlying DNA sequence.

Even if that sort of approach works, huge safety questions remain. “Faulty imprints do give rise to human diseases,” says Azim Surani at the University of Cambridge, who discovered the imprinting phenomenon in 1984. Any manipulation of imprints could therefore have serious consequences, he says. ■

Mice pups born to same-sex parents

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“ We’re now saying it’s 2500 years old based on our estimates of growth rate, and that’s a lower bound”

A HUGE fungus that is one of the

largest living things on the planet

turns out to be both bigger and older

than thought. It may have been

spreading through the soil of Michigan

since the end of the last ice age and

weighs at least 400,000 kilograms.

James B. Anderson at the University

of Toronto in Canada and his

colleagues found the honey fungus

Massive fungus is older than Christianity

Armillaria gallica in the late 1980s,

while studying other fungi that

were killing red pines on a Michigan

plantation. It spanned at least 0.37

square kilometres. At the time, they

estimated it was at least 1500 years

old and weighed at least 100,000 kg.

Back then, the fungus was a

contender for the largest living

organism, but bigger fungi have

since been found.

Anderson and his colleagues have

now revisited the fungus, which had

been left to its own devices since

the early 1990s. They collected

245 samples, far more than before,

allowing them to get a better sense of

its shape below ground. The fungus

weighs at least 400,000 kg, four

times larger than the initial estimate.

The fungus grew from a single

individual, so its greater size implies

it is also older than thought. “We’re

now saying 2500 years based on our

estimates of growth rate, and that’s

a lower bound,” says Anderson.

It could be much older. The upper

limit is the end of the last ice age,

about 11,000 years ago, because

that’s when Michigan’s forests began

to grow. “It may go all the way back to

post-glaciation, when the forest was

re-establishing on that site,” says

Anderson (bioRxiv, doi.org/cvq6).

The team was also able to estimate

how many genetic mutations the

fungus has accumulated over its life,

a rate Anderson says is “almost

impossibly low”. It’s not clear how

the fungus manages this: it may be

unusually good at repairing DNA

damage, or have a purposely slow rate

of cell division. Michael Marshall ■

One of the newborn mice

created by researchers in China



NEWS & TECHNOLOGY

THE US Marines are developing a

laser weapon that can transmit voice

messages at long range – or be turned

up to deafen or cause painful burns.

The Scalable Compact Ultra-short

Pulse Laser System (SCUPLS) will be a

non-lethal weapon for crowd control,

according to US Navy documents.

The weapon builds on previous

prototypes developed by the

Pentagon. An igniter laser fires an

intense pulse lasting just a few

million-billionths of a second. This

creates a ball of plasma, which can be

created in mid-air or on the surface

of a target. A detonator laser then

explodes the plasma ball, resulting

in a flash and a bang.

At the lowest power setting, a

rapid series of flash-bangs will be

modulated to carry robotic speech,

conveying instructions over distances

of up to 100 metres.

At higher levels, it will produce

flash-bangs as loud as the inside of

a jet engine and dazzlingly bright.

When aimed at a person, SCUPLS

will painfully vaporise the outer

layer of skin. The weapon is likely

to be mounted on a small vehicle.

Previous weapons have been

limited by the strength of available

lasers. “They cannot, to-date, provide

the full laser performance necessary

to deliver all three of the desired

non-lethal effects,” the Pentagon

told New Scientist. The SCUPLS

project will work to increase both

the power per pulse and the number

of pulses per second.

SCUPLS could be more adaptable

than existing crowd-control weapons.

For example, an individual can be

ordered to stop or put down a weapon.

If they fail to comply, SCUPLS could

apply increasingly unpleasant effects

until the individual complies.

But it is not clear how safety will

be ensured. “Dosage will be decisive

for avoiding permanent injury,” says

Jürgen Altmann at Dortmund

University of Technology in Germany.

David Hambling ■

Laser weapon shouts, then burns people

Chelsea Whyte

POLICING power may be about to get much stronger, thanks to an advance in genetic analysis. A new technique can link the limited DNA information held in forensic databases to the rich DNA libraries held by family tree-building websites – which raises questions about genetic privacy.

Earlier this year, police identified someone they suspected was the Golden State Killer – a serial killer active in California decades ago – with the help of an ancestry database used by people looking to trace their family history.

Since the arrest in April, genealogy databases – which allow consumers to upload their DNA sequences – have been used to crack several other cold cases.

Police are turning to consumer genetics databases because the forensic ones hold only limited genetic information.

The US national DNA database used by police and the FBI – called CODIS – doesn’t store whole DNA sequence data. Instead, it focuses on up to 20 specific stretches of repetitive DNA code that are relatively easy to sequence. These regions vary between individuals, so can help identify people.

Consumer genetic databases store different data: single-letter variations in DNA across

hundreds of thousands of sites in the genome. Because they carry more information, these commercial databases can more accurately pin down a person’s relationship to others.

“When police have DNA evidence, usually it’s very minute quantities,” says Yaniv Erlich of genetic ancestry company

MyHeritage. “Currently, they have this dilemma: should we run a CODIS set on our DNA or use the more sophisticated techniques?”

Now Noah Rosenberg at Stanford University in California and his colleagues have developed a computational model that makes it easier to link people in CODIS to those in genealogy databases.

The model relies on the fact that some of the single-letter variations recorded by ancestry databases are gathered from roughly the same part of the genome from which the longer stretches of DNA recorded in CODIS come from. This gives potential overlaps.

Rosenberg and his team tested the model with data from 872 people. They found that they could identify about 35 per cent of sibling pairs by comparing CODIS-like DNA from one member of the pair with ancestry database-like DNA from the other member of the pair (Cell, doi.org/gfb8w6).

“This could expand the number of cold cases that are solvable,” says Natalie Ram at the University of Baltimore, Maryland. She says it also raises questions about how private our genetic information is.

The CODIS system was designed to be minimally informative, so that it can’t reveal information beyond identity, says Rosenberg. But the DNA data in genealogy websites can reveal physical or medical characteristics, so the ability to link between the systems might make it possible to find out more about a suspect from their DNA.

However, at least for the moment, the number of matches between CODIS and consumer sites is limited. This is because CODIS is dominated by DNA samples from minority groups, while genealogy sites are mostly used by white people of European descent. ■

Crime scene DNA gets more revealing

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“ This could expand the number of cold cases that are solvable, but it also raises privacy questions”

Most of a sample’s genetic data is

ignored in the search for a match


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IF A female mouse has a fatty diet just before, during and just after pregnancy, her pups, grandpups and great-grandpups have a raised risk of obesity and addiction.

Animal studies have shown that such a high-fat diet can lead to offspring with a less sensitive reward system: they need more food to feel full and are more susceptible to becoming obese or addicted to drugs.

Daria Peleg-Raibstein at the Swiss Federal Institute of Technology in Zurich and her colleagues wondered about the impact on the second and third generations. They fed female mice a high-fat diet for three weeks before they mated, and six weeks after. The male offspring were bred with female mice who had been fed a normal diet to produce a second generation, and those

male offspring created a third. Both were found to have a

7 per cent greater body weight and a greater preference for alcohol than normal mice. They also had less dopamine, the brain’s signal for pleasure, and more dopamine receptors. Both brain changes may have increased the amount of food and alcohol the mice needed to feel satisfied (Translational Psychiatry, doi.org/cvqw). It is too early to say if this has implications for people, says Peleg-Raibstein.

IN BRIEF

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Our memories are packed with thousands of mugshots

YOU can probably recognise a lot more faces than you

might think, typically about 5000.

“It seems to be overkill,” says Rob Jenkins at the

University of York in the UK. That is because humans

lived in groups of around 150 people for most of our

evolutionary history, so the usual idea is that it makes

sense for us to recall about this number of faces.

To test this idea, Jenkins and his team asked

25 people to spend an hour writing down the people

they knew personally for whom they could form a clear

mental image of their face.

On average, participants listed 40 people in the first

5 minutes of the exercise and 21 in the final 5 minutes.

From these rates,the team calculated that a typical

participant would have listed 549 people if they were

given unlimited time.

Then they tested recognition of famous faces by

showing images of 3441 public figures from the likes of

film, business, politics and sport. Each participant saw a

different picture of each figure on separate days. If they

said they recognised the celebrity in both pictures, that

person was considered part of their “facial vocabulary”.

Participants recognised about 30 per cent of these

faces. Based on this, Jenkins and his team estimated that

most people can recall about 5000 faces (Proceedings of

the Royal Society B, doi.org/cvqb).

Diet of pregnant mice affects grandpups

Pills jiggle to get your bowels going

CAPSULES that vibrate in the gut can ease constipation.

The usual advice for those with the condition – to eat more fibre, exercise and take laxatives – doesn’t always work.

To address this, Israeli firm Vibrant has developed capsules the size of fish oil supplements that vibrate in the large intestine to stimulate contractions that move digestive products along.

Satish Rao at Augusta University in Georgia and his colleagues tested the capsules in two clinical trials involving 245 people with chronic constipation.

Participants took capsules for eight weeks. Half had versions set to vibrate in the large intestine. The others had non-vibrating placebos. The vibrating capsule group had twice as many bowel movements per week. Rao presented the results at the annual meeting of the American College of Gastroenterology last week.

Algae could ferry drugs in your body

SOME algae can swim surprisingly fast, a talent that may make them an ideal drug delivery system.

Metin Sitti at the Max Planck Institute for Intelligent Systems in Germany and his colleagues figured out how to attach tiny magnets to a freshwater alga. Then they applied a magnetic field to control the direction it swam in (Advanced Materials, doi. org/gd93zt).

The aim is to load algae with drugs and steer them to diseased tissue. At present, a drug must be applied to a wider area or the entire body, which can cause unpleasant side effects.

The team is working on ways to ensure immune cells don’t attack the algae before they reach their destination.



For new stories every day, visit newscientist.com/news

Eclipse didn’t get the bees buzzing

BEES suddenly went quiet during

the solar eclipse that swept across

North America in August last year.

A set of 16 monitoring stations

recorded them falling silent as

the moon totally covered the sun.

Candace Galen at the University

of Missouri and her colleagues set

up microphones in stands of flowers

along the path of the eclipse, from

Oregon to Missouri, to listen to bees.

They found that as the moon

started to move in front of the sun,

the bees continued buzzing. But

in the period around totality, the

sound, created by the bees’ wings

as they fly, suddenly dropped off.

“We had expected to see a

reduction in activity, but we

thought that it would be gradual

following the loss of light,” says

Galen. “We didn’t expect everything

to go along as usual until totality.”

The team recorded sound for

3 minutes – covering the period

of totality that lasted 40 to 160

seconds depending on the

location – and found that only one

bee buzzed during those 3 minutes

(Annals of the Entomological

Society of America, doi.org/cvp9).

It isn’t clear whether the other

bees flew back to their hives, as

they do at night, or whether they

sheltered in flowers, as they do in

inclement weather. “All we can say

is what they weren’t doing – they

weren’t flying,” says Galen.

Scat lets rabbit know it’s on the menu

IF YOU are a rabbit, it is vital to know

when predators are around. It is

even more useful to know if they are

eating your kind, and it seems rabbits

can do this by detecting the whiff

of a digested bunny in droppings.

The European rabbit is a very

popular meal for predators – more

than 30 species eat it, says José

Guerrero-Casado at the University

of Cordoba in Spain.

This rabbit has an impressive

ability to smell predators. But

Guerrero-Casado and his colleagues

wondered if it could also tell if a

predator had already eaten rabbit

from the scent of its droppings.

The researchers ran an experiment

in the Spanish countryside. One area

was sprayed daily with an extract of

scat of ferrets on a beef-based diet.

Another was sprayed with the scat

odour from ferrets on a rabbit-based

diet. The third was sprayed with

water as a control.

Guerrero-Casado’s team counted

rabbit droppings on the plots to

gauge how often the animals were

visiting to feed. They found fewer

droppings in the area sprayed

with rabbit-based scat odour

(Acta Ethologica, doi.org/gd9948).

WHAT are the best two legs for acing an obstacle course? For an AI: one that pulls you forward by flexing at the knee joint, and one massive leg pulled behind for stability like a kangaroo tail.

David Ha at Google created a virtual robot with a wide head. It had two legs that it could design itself. He tasked it with crossing a randomly generated virtual landscape within a set time. The artificial intelligence learned to do this with an algorithm that rewarded it with points for supporting its head,

reaching the exit and not falling over. This encouraged it to find the best leg designs.

When the terrain was fairly flat, the AI crossed most quickly with a jaunty, skipping gait performed on the “knees” of long, skinny legs. This beat walking on the “feet” of shorter, thicker legs.

When facing a landscape with pits and obstacles to climb, the AI developed one long, skinny leg that it used to sense obstacles, and a larger hind leg dragged in its wake to stabilise itself.

As is usual when you give

artificial intelligence free rein, high jinxs ensued. When given no constraints and asked to cross an obstacle-laden course, the AI built an extremely tall bipedal creature that simply fell down to reach the exit. When rewarded for building smaller legs, the AI took that to an extreme, tottering on tiny legs across a fairly flat surface.

An algorithm like this could come up with designs we had never thought of and that outperform ours, wrote Ha (arxiv. org/abs/1810.03779).

AI invents weird limbs to conquer virtual landscape

Why T. rex wasn’t such a big noise

IT IS easy to think Tyrannosaurus rex was so large that the ground shook as it approached. But it seems the dinosaur made less of a rumble than expected.

Heavy animals produce earthquake-like seismic waves with every footfall. We know that other animals can detect these.

Large dinosaurs must have produced seismic waves too. Ernesto Blanco at the University of the Republic, Uruguay, and his colleagues decided to investigate. They analysed 64 fossil footprints left by large dinosaurs, including herbivores, omnivores and carnivorous theropods – a group that includes T. rex. The theropods had a more elongated foot.

When they simulated the seismic wave pattern generated when the various dinosaur feet hit the ground, they found the waves from theropod feet were weakest in the walking direction. In other words, theropods had a foot shape that would have allowed them to sneak up on their prey, seismically speaking.

Blanco suggests that elongated feet may have evolved because they gave theropods a hunting advantage (Journal of Theoretical Biology, doi.org/cvq3).

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IN BRIEF


Where did we come from?

How did it all begin?

And where does belly-button fluff come from?

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Introduction by Professor Stephen Hawking


“The world is facing a huge challenge,” says Kathrina Mannion. The global population is rising and expected to reach 9 billion by 2040. The standard of living is rising for many people, who want access to transport, to nutritious and plentiful food supplies, to development and so on. To achieve all this, they need energy.

“But how are we collectively going to meet this massive demand while also reducing emissions?” she asks. The issue is that greenhouse gases are emitted through use of fossil fuels in activities such as transport, power, heating and agriculture. But these gases play a role in global warming.

Mannion’s question may sound unusual given that she works for BP, one of the world’s biggest oil and gas companies. But that’s the point. BP believes it has a key role to play. And Mannion is heading a unit inside the company that is helping drive action across the business.

“No one company or sector alone can deliver a low carbon future. Everyone, from consumers to corporations to governments, needs to take responsibility. At BP we’re asking what we can do to help to play a role in addressing this challenge,” she says. “As part of that we launched the Advancing Low Carbon programme,” for which she is the programme director.

Earlier this year, BP announced a number of new low carbon targets. “We’re trying to reduce emissions in our own operations, to improve our products to help our customers reduce their emissions, and also to create new low carbon businesses. The Advancing Low Carbon programme is looking to encourage more action in all of these areas,” says Mannion, who has a degree in ecology.

For example, BP is one of the top wind energy producers in the US, generating 2259 MW of renewable power. That’s enough to power every home in Philadelphia.

But it’s not just renewable energy sources she is focusing on. “We know that the world

The world needs more energy but delivered with fewer carbon emissions. Embracing that dual challenge is the way BP thinks about every aspect of its business, says Kathrina Mannion

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Towards a low carbon future

“ BP is focusing on carbon emissions in every aspect of its business”

will be using fuels and lubricants for many decades to come. So we are looking at ways to make those the most efficient or low carbon fuels and lubricants we can,” she says.

One example is Biojet, a lower carbon jet fuel made partly from recycled cooking oil that BP sells in Sweden and Norway. This reduces greenhouse gas emissions by more than 60 per cent compared to standard jet fuel.

This low carbon thinking can be seen in BP’s lubrication business too. Its Castrol business has developed an innovative new way to change and recycle used engine oil, set to hit the market after 2020 (see “All Change”, opposite) and a range of carbon neutral lubricants.

Applying this kind of innovative thinking to its shipping fleet means that BP tankers operate more energy efficiently too.

BP has also invested in external companies that have potential to reduce carbon emissions . A good example is Solidia Technologies, which has developed a form of cement that captures and stores carbon dioxide as it dries.

The ability to quantify the impact of these efforts is a crucial part of the Advancing Low Carbon programme. Mannion is adamant that these figures must be supported by evidence and clear and provable data. So the figures and the approach are all checked by independent observer Deloitte to ensure that it is thorough. “We’ve brought in an external partner who looks at these activities to check our figures and make sure they are robust and verifiable,” she says.

The Advancing Low Carbon programme is beginning to change BP from the inside by energising low carbon thinking. “We need to think right across the company how we can encourage and drive low carbon action,” says Mannion. “To deliver significantly lower emissions, every kind of energy needs to be cleaner and better.”

More at: newscientist.com/BP

Kathrina Mannion,

BP’s Advancing Low

Carbon programme

director

Right: Biojet is

a lower carbon

aviation fuel

Below: BP is one

of the top wind

energy producers

in the US


Nexcel is a reusable and easily replaceable

cell, like a cartridge, that contains all the oil

for an engine along with the oil filter. It’s being

developed to be engineered into cars of the

future. So an oil change will be as simple as

lifting out the cell and replacing it with

another, which takes about 90 seconds.

Because the used oil is contained, all of it

can be recycled. That has significant benefits.

The world produces about 6 billion litres of

used engine oil every year but only about a

quarter is recycled. In fact, about 2 billion litres

is not recovered by licensed waste companies

and so ends up in local waste streams,

where it can be hugely damaging.

Nexcel will allow engine oil to be efficiently

recycled and reused. It also does away with

the need for oil to be stored and sold in single

use plastic containers.

The system can also improve engine

efficiency. One factor that determines this

is the temperature of the engine oil. The oil

becomes less viscous, reducing friction

within the engine, as it heats up. That’s one

reason why hot engines are more efficient.

In contrast, an engine running on cold oil uses

up more fuel and is therefore more wasteful.

When a conventional engine starts from

cold, it has to heat all the oil in the sump –

usually around 5 litres. “That’s a large volume

of oil to be heated before you reach the

optimum temperature,” says Rachel Fort,

a chemist who is a senior formulation

technologist at Nexcel.

But the Nexcel system feeds oil into the

engine in small, precisely controlled amounts

that quickly heat up. So the engine can

operate more efficiently from the start.

In-house testing indicates that this, along

with other lubricant technologies enabled

by Nexcel, could translate to a reduction in

carbon dioxide emissions of 2 grams for every

kilometre driven. “That may not sound like

much, but every gram is important, “says

Fort. “Over the lifetime of a vehicle, that

equates to about a third of the vehicle mass.”

Above centre:

Rachel Fort, Nexcel

Above: The Aston

Martin Vulcan uses

the Nexcel system

All change



“ZERO suicide” is the phrase of the moment in mental health. Thanks to a programme in Detroit that managed to push rates of suicide to zero within a few years, the approach has spread to health bodies all over the world. Last week, the UK government appointed England’s first minister for suicide prevention, on the back of a “zero suicide ambition” for patients in the care of the National Health Service announced in January.

Reducing the number of suicides is clearly a desirable goal. Yet some doctors view the zero suicide movement with alarm, fearing that such a challenging goal may actually be counterproductive.

Some of the earliest successes in suicide prevention simply involved changes that made it more difficult for people to take their own lives. Proponents point to the unintended benefit seen in the UK in the 1960s when the gas supply to people’s homes gradually became less poisonous. At the time, deliberate gas inhalation accounted for about

half of UK suicides. By the end of the 1960s, the total suicide rate had dropped by a third.

More recently, deaths seem to have been avoided by a change in UK law to restrict pack sizes of the painkiller paracetamol, also known as acetaminophen. From 1998, the tablets could only be sold in small quantities. Ten years later, deaths from paracetamol poisonings had halved.

Effects like these show that suicidal thoughts can sometimes be transient, says Keith Hawton at the University of Oxford. “If you can keep people safe until those thoughts diminish, you can save lives.”

Hawton recalls a former patient who had somehow survived a jump from a high bridge. “When he hit the water, he damaged his body very badly, breaking many bones. Yet his first thought was to

try to swim to the side.” Hawton says many other suicide survivors report similar changes of heart.

Efforts are still ongoing to make it physically harder for people to take their own lives, particularly in psychiatric hospitals, for instance by removing objects that could enable hanging. A more radical approach is to try to proactively identify those likely to attempt it, an approach called suicide screening.

This was at the heart of the programme that helped start the zero suicide idea. It was pioneered in 2001 by a Detroit-based healthcare provider called the Henry Ford Health System. Anyone who came into contact with its mental health services was screened for suicide risk, and safety measures were taken if they were deemed necessary. These included asking the person if they had had any thoughts of suicide and how they would do it, then putting obstacles in place.

Often, this meant getting rid of any guns from the house – about two-thirds of gun deaths in the US are suicides. “Many people think if you get rid of this gun they’ll just go find another gun,” says Ed Coffey, who helped introduce the scheme. “For some reason, getting rid of the one they have fantasised about seems sufficient.”

Other elements included improving access to doctors, and making sure people had a “safety plan”: personalised guidance on what to do if they had suicidal impulses, including phone numbers of friends and family to call for help. And a broader

depression screen was offered to those seeing doctors for reasons unrelated to mental health – such as those visiting primary care or hospital emergency rooms – so they could be funnelled into suicide screening if necessary.

Downward trend

Within a few years, the suicide rate among those accessing mental health services had fallen, and in 2009 the number hit zero. The programme’s architects began publicising the results and it has since been emulated by health bodies in more than 100 countries. Methods vary, but the driving philosophy is a refusal to accept that any suicide is inevitable. Proponents include

INSIGHT SUICIDE PREVENTION

Inside the plan to end suicidePoliticians say they want to aim for zero suicide, but that target might be counterproductive, says Clare Wilson

Detroit healthcare provider Henry Ford Health System’s suicide screening, introduced in 2001, seemed to help stop deaths entirely, for a year

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“The philosophy of the zero suicide movement is a refusal to accept that any such deaths are inevitable”



bereaved parents who are determined their child’s death will not be in vain.

So why the scepticism? One problem is that there is little evidence to show that some elements of the scheme work. There is particular concern over suicide screening, because no questionnaire can reliably identify who is going to take their own life, says Hawton. Studies show that there is a higher rate of suicide among those classed as high risk, but about half of people who take their own lives would have been classed as low risk. “Assessments are extremely inaccurate,” says Hawton.

How did they work in Detroit? Perhaps they didn’t. The suicide rate among Henry Ford Health

System’s mental health patients these days is certainly lower than before 2001, suggesting services have improved. But according to the provider’s published data, the suicide rate was falling before the programme started (see graph, left), and the current rate is nothing out of the ordinary.

Suicide is a rare event – with an annual rate of about one in 10,000 people – and so the provider only has a handful of cases a year among its mental health patients. The figure has jumped up and down since 2001,

For daily news stories, visit newscientist.com/news

but only in 2009 was it actually zero. “With such small numbers, a year without any suicides could occur by chance,” says Hawton.

Another caveat is that the headline zero figure was for people using mental health services. In the UK, about seven in 10 people who take their own lives haven’t had any such contact in the past year. It is a tall order to expect doctors to save the lives of people they haven’t met.

“One of the big challenges is reaching out to people who are not in contact with health services,” says David Gunnell of the University of Bristol, UK.

Yet these days, the term zero suicide is usually taken to apply not just to those under a doctor’s care, but to everyone. Politicians have called for their localities to become “zero suicide cities”. For instance, last year London Assembly members did so, citing Detroit’s example. Sweden has adopted a “vision zero” for the entire country.

Amid a gathering wave of concern for mental health, the zero approach has taken on a life of its own, with a variety of interpretations. For the Mersey Care NHS Foundation Trust, one of the first mental health trusts to adopt it in the UK, it includes making sure all patients get a safety plan, as in Detroit, as well as improving staff training.

Another key aspect is an incident report after every suicide, to work out how it could have been avoided. Mersey Care medical director David Fearnley says the goal of zero was crucial for changing the mindset that some suicides are inevitable.

In Sweden, though, critics complain that the goal hasn’t led to any specific measures or significant new funding. So it feels like an empty slogan – one that comes with potential downsides, says Herman Holm of Skåne University Hospital in Malmö.

Holm worries it could lead to more compulsory psychiatric treatment. The decision to keep

someone in hospital against their will is always a delicate balance between their liberty and their risk of self-harm. “A zero suicide target risks scaring psychiatrists into depriving too many people of their freedom,” says Holm.

But the chief grievance is that zero suicide sets a target that is not realistically going to be met. “Eliminating suicide completely is not going to happen,” says Hawton. “Throughout history, suicides have occurred.”

It is unclear what hearing claims that “all suicides are preventable” does to bereaved

families. For some, “the idea that suicide should not happen makes them feel worse”, says Hawton. “It adds to their burden.”

Then there is the effect on doctors and nurses, says Simon Wessely, past president of the UK’s Royal College of Psychiatrists. “Impossible targets rebound on staff morale. You’re increasing the blame culture when it’s not achievable.”

But Fearnley says that’s not how it works within Mersey Care. Although the trust mandates incident reports after each suicide, he says they have a blame-free culture. “It has given people permission to start asking questions about deaths, and being far more curious to ask what else we could have done.”

The sceptics stress they applaud new suicide prevention initiatives, but they don’t think the goal should be framed this way. Some say it would be more useful to change it from being a hard target to an aspiration, one meant to inspire people rather than be taken literally. “I believe it should not be a target but a reminder that there are ways we can reduce suicide risk,” says Wessely. “If that happens, I’m all in favour.” ■

“I believe it should not be a target but a reminder that there are ways we can reduce suicide risk”

Need a listening ear? UK Samaritans:

116123 (samaritans.org). Visit bit.ly/

SuicideHelplines for hotlines and

websites for other countries



COMMENT

Support neededBaby Loss Awareness Week is a start, but more must be done to help those who, like me, have lost a pregnancy, says Petra Boynton

ANYONE who has experienced a miscarriage, stillbirth or other pregnancy loss will understand the pain, distress and uncertainty that can follow.

Because these experiences are common, you might hope that the way we help people during and after the event would be uniformly good.

Unfortunately, this is not the case. Back in 2016, The Lancet noted that half of the world’s 2.6 million annual stillbirths are preventable. And there are huge inequalities globally, with 98 per cent of stillbirths happening in low-income countries.

The quality of training for healthcare workers is also patchy, with staff often struggling to stay up to date with the latest evidence, or to provide effective care in overstretched services. Where training is provided, it tends to focus primarily on

physical issues – preventing accidents and dealing with pregnancy or birth problems – rather than emotional needs.

Providing compassionate care also requires us doing better at identifying and recording loss – stillbirth rates are thought to be underestimated by a third.

The World Health Organization uses an international cut-off point of fetal loss after 28 weeks for recording stillbirth. Researchers and practitioners are asking for stillbirths to be recognised and recorded from 22 weeks, allowing for more investigations into its potential causes. Parents simply want better opportunities to recognise their losses and remember their babies.

All this means that healthcare workers can’t offer the care they would like to people who have lost a pregnancy. In the UK, the National Bereavement Care

Smoke signalsUK’s halting step towards cannabis legalisation leaves patients in limbo, says Henry Fisher

ANY government looking to regulate medical cannabis has to chart a careful course. If you implement a system that is too permissive, it is simply a facade for non-medical use. And one that is too restrictive will fail to provide for patients.

In a policy shift that will legalise the sale of medical cannabis

products on prescription as of November, the UK government has chosen to steer far closer to the second option.

Cannabis not produced for medical use in humans remains a class B, schedule 1 prohibited substance. Cannabis-based medical products, however, will become schedule 2 medicines,

with one major exception: when they are smoked. In a bid to prevent confusion for police, smoking cannabis will remain illegal, regardless of its origin. Those prescribed cannabis won’t be permitted to medicate themselves with the aid of a flame.

And getting the medication won’t be easy. Only specialists can prescribe the cannabis, following a referral from a doctor. For these regulations to lead to even modest levels of patient access, a huge

programme of education among healthcare professionals will be required.

As groundbreaking as this change is for UK drugs policy, the new amendment seeks only to regulate the medical use of a product that has both an established medical need and a substantial non-medical demand. This is not a recipe for success.

Many patients who are unable to access cannabis legally due to the overly restrictive regulations will seek it out either through the illegal market or by cultivating it themselves.

Lessons should be learned from other legalisation efforts, notably

“ Many patients will be unable to access cannabis legally due to over restrictive regulations”



Leah Crane

THE near future of human space flight is looking dangerously uncertain. On 11 October, a Russian Soyuz craft carrying two astronauts to the International Space Station (ISS) had an issue with one of its boosters, causing a crash landing about 400 kilometres from the launch site in Kazakhstan.

Fortunately, the astronauts are alive and well, but the failed flight may complicate things on the ISS.

US astronaut Nick Hague and Russian cosmonaut Alexey Ovchinin, are in good condition, but after a bumpy ride – including g-forces of six or seven times the gravity on Earth’s surface – it could easily have gone another way. The average person might pass out under forces of 5 g.

This malfunction is particularly troubling because the Soyuz rocket and capsule are the only spacecraft currently capable of carrying humans to the ISS. All crewed Soyuz launches are suspended until NASA and the Russian space agency Roscosmos figure out what happened and how to prevent it in the future. That means no one can now reach the station.

This accident, coming on the heels of an air leak in the last crewed Soyuz to visit the ISS, may mark a point of reckoning for human space flight. That damaged Soyuz, which is currently docked with the ISS, is the only way for the three astronauts on board to return to Earth.

The hole has since been repaired, and is in part of the spacecraft that isn’t important for re-entry to Earth’s atmosphere. Even so, the docked Soyuz will reach the end of its official safe lifetime in space in early January.

Past then, Roscosmos will have to send up an empty Soyuz to get the crew back to Earth.

That puts the three astronauts in a tough place: they can come home, abandoning the station, or they can extend their missions until the Soyuz or another craft is ready to send new astronauts to replace them. Supplies will not be a problem, because there are several other uncrewed spacecraft

that can bring food and fuel.There is a possibility that the Soyuz

craft will be grounded for a long time. NASA is notoriously careful when it comes to astronaut lives, and the agency may not wait for Soyuz to get to three strikes.

But what then? NASA retired the space shuttle in 2011 with plans to quickly replace it with capsules made by SpaceX and Boeing. Delays and budget cuts mean these new spacecraft now won’t be ready until mid-2019 at the earliest. Stringent NASA attitudes about risk and testing make it unlikely these flights will be accelerated, even in an emergency.

China is now the only country with a working craft capable of taking humans to space, but it has only ever launched six missions and is currently excluded from the International Space Station programme. Theoretically, its Shenzhou craft, which is based on the Soyuz design, could dock with the ISS, but such a mission would require an extraordinary act of geopolitical negotiation and technical ability.

If the astronauts do come home without being replaced by a new crew, the ISS will be empty for the first time since 2000. If it remains empty, the lack of upkeep could doom the already ageing station, taking down one of the world’s most valuable and important assets in space. For the want of a proverbial nail, humanity’s exploration of the universe could be set back by decades. ■

Soyuz crash leaves the ISS in a grim spot

ANALYSIS Human space flight

NA

SA

“For the want of a proverbial nail, exploration of the universe could be set back by decades”

For more opinion articles, visit newscientist.com/opinion

Pathway is seeking to change things and “ensure that all bereaved parents are offered equal, high quality, individualised, safe and sensitive care in any experience of pregnancy or baby loss”. This is a welcome development in my view, because the poor care I received after one of my miscarriages turned an upsetting event into a far bigger trauma that in turn affected my future pregnancies, losses and mental health.

Speaking about the loss of a pregnancy shouldn’t be a taboo, but it remains one. Many charities are pushing for greater awareness and to break the silence over pregnancy loss, with events such as Baby Loss Awareness Week, which ended on Monday. All of this is admirable, but these conversations can’t just be led by those directly affected by loss. They need to be heeded and joined by those offering care and undertaking research.

Without joined-up studies, care and training, and referrals to sources of support, pregnancy loss will continue to be a difficult path that many of us should not have to walk alone. ■

Petra Boynton is a social psychologist working in healthcare and author of Coping With Pregnancy Loss (Routledge)

in Germany and Canada. Now on its third attempt to regulate medical cannabis, Germany is struggling with tight restrictions, low supply and issues of poor doctor education. Canada, meanwhile, implemented a fully legal cannabis market for adult use this week, having come to the conclusion that the only way to maintain an effective medical market is to also regulate non-medical sales.

The UK would do well to take a leaf out of the Canadians’ book. ■

Henry Fisher is the chief scientific officer of Hanway Associates, a global cannabis consultancy in London


APERTURE




Fresh perspectives

THE cenotes of Mexico’s Yucatán peninsula are

undeniably magical places. These large sinkholes,

formed by the dissolution and collapse of

limestone bedrock, expose groundwater

beneath. In this arid land with almost no rivers

or surface lakes, they became a vital source of

drinking water. The discovery of precious

artefacts and human skeletons in some cenotes

confirm the sacred esteem they were held in by

the Mayan civilisation, who believed they were

gateways to the underworld.

This image, and those on the following two

pages, are from the Freshwater Project, a global

odyssey by Swiss photographer Michel Roggo

covering 40 locations across the world between

2010 and 2017. The project serves to illustrate

the phrase ”still waters often run deep”. It also

shows the diversity of environments found in

fresh water, which often matches that of more

familiar terrestrial ecosystems.

The diver in this picture is Camilo Garcia,

investigating the Dos Ojos, or “two eye” cenote,

named for its two openings at ground level. It is

one of the cenotes along the Yucatán’s Caribbean

coast, where fresh water meets seawater in

extensive networks of underwater passages.

A connection between the Dos Ojos and the

neighbouring, larger Sac Actun system,

discovered only in January 2018, makes this the

longest underwater cave system known, with a

total length of over 300 kilometres. Richard Webb

Photographer

Michel Roggo / NaturePL

roggo.ch


APERTURE

28 | NewScientist |

APERTURE


Top: Michel Roggo learned his craft

among the rivers, lakes and glaciers of

the Swiss Alps. In the spring of 2013,

a prevailing southerly wind brought

sand from the Sahara to these high-

lying waters. “All the mountains and

the glacier were yellow and orange

from it,” says Roggo. In September that

year, those hues were still visible in

meltwater sediments from the Gorner

glacier on the Monte Rosa massif.

Top: Thanks to a natural filtration

system, Rotomairewhenua, or Blue

Lake, in New Zealand’s Southern Alps

has the planet’s clearest waters. They

are sacred to the Ngati Apa ki te Ra To,

who use them to cleanse the bones of

the dead. “You cannot fish or swim in

this water, or drink or touch it,” says

Roggo. He had to obtain special

permission to photograph it using

a remote-controlled pole camera.

Bottom: Hidden among water hyacinth

plants, a yacare caiman waits for

passing prey in the Pantanal wetlands.

Sprawling over a vast area from the

Brazilian state of Mato Grosso do Sul

into Bolivia and Paraguay, the

Pantanal is one of the most biodiverse

ecosystems on Earth. Its caiman

population is estimated to number

10 million – the largest crocodilian

community on Earth.


wScientist | 2920 October 2018 | NewScientist | 29

Top: The forests of the Gunung Mulu

National Park in Malaysian Borneo

house a rich diversity of animal and

plant life. But if Roggo was expecting

a similar picture when he dipped his

head beneath the surface of the

Sungai Melinau Paku river, he was

disappointed. “I saw not a single

aquatic plant in all the creeks, ponds

and rivers,” he says – just washed-off

debris from the surrounding trees.

Bottom: Beauty doesn’t need clarity,

as shown by the reddish, acidic water

of Etang de la Gruère in the Jura

mountain range of western

Switzerland. Laced with tannins from

surrounding pine trees, such waters

rich in dissolved organic matter are

known as blackwaters. The Rio Negro,

a tributary of the Amazon, is perhaps

the most famous example, and they

are common in the southern US, too.

Bottom: The “underwater garden”

of Ewens Ponds in South Australia is

formed of three flooded limestone

sinkholes around 10 metres deep,

connected by shallower watercourses.

The water’s extraordinary clarity lets

the plants and the algal blooms seen

here thrive up to 6 metres down. As in

many places, the fresh water here is

under threat as agricultural run-off

changes its natural chemistry.



COVER STORY

Fasting diets seem here to stay and the evidence that they are good for you is stacking up. Caroline Williams tries one for herself

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AS I unpack my rations for the next five days, I start to question what I have signed up to. For years I have

heard the hype about fasting diets and what they promise: smaller thighs, a clearer head, a lower risk of cancer, heart disease and diabetes and the promise of a generally longer, healthier life.

But then there is the hunger. Hunger makes me angry, and tired, and generally not a very nice person. So I have always given fasting diets a miss: the 5:2 diet where you fast for two days a week and eat normally the others; the 16:8 where you eat within an 8 hour window, and fast for 16; the alternate day fasting. You name it, it seems someone has tried it.

Then I heard about one of the latest trends, the fasting mimicking diet. If the marketing materials are to be believed, it is the holy grail: all the health benefits of fasting without the hunger. The company behind it has even become the first to be granted a patent for boosting human healthspan before the onset of disease. So can I really have my cake and eat it? I decided to give it a go – and try to get to the truth about fasting.

We have known for decades that restricting calories can have beneficial effects – if not in humans, then in animals. Many studies have found that organisms from single-celled yeasts to rodents age more slowly and live longer when their calorie intake falls to 40 per cent of that consumed by a group of animals eating normally.

Constant calorie restriction has never really caught on in people, however, not least because the results didn’t bear out in primates. Besides, people find it difficult to restrict their diet in this way for long enough to find out if it extends their lives.

Fasting has been part of religious practice around the world for millennia, but it first made it into the consumer mainstream around five years ago, on the back of animal studies and research in overweight people suggesting that skipping meals could have numerous health benefits. There is growing evidence that periodically going without food puts our bodies into a kind of emergency mode, where they conserve energy, make repairs and prioritise mental clarity to solve the problem of finding food. “If we accept that the Palaeolithic was the environment in which most modern human adaptations were shaped, including dietary ones, the hunter-gatherers then were adapted to periods of feast and famine,” says Stanley Ulijaszek, a nutritional anthropologist at the University of Oxford. “This could well be a more

natural state for us than ‘three meals a day’.”As well as weight loss, proponents claim

that intermittent fasting could help protect against cancer, diabetes and disorders like Parkinson’s and Alzheimer’s disease.

My own enthusiasm at the promise of a hunger-free fast diminishes somewhat as the kit arrives. I would be living off two packet soups a day, plus a few crackers, olives and the odd nut bar. It looked a lot like hunger to me.

This particular diet is the brainchild of Valter Longo, a gerontologist at the University of Southern California in Los Angeles. The basic claim is that fasting just once a month – albeit for five days – can mimic the effects of fasting seen in animals, even reversing the effects of ageing. The website of Longo’s spin-off company, ProLon, says that the fasting mimicking diet is “clinically proven to induce the [body’s] protectionist and rejuvenation mode”, while providing enough calories that you don’t actually pass out.

Anyone can benefit from this cellular spring clean, says Longo: “It doesn’t matter how good your diet is, it doesn’t matter how much exercise [you do], the body ages and the cells accumulate damage.”

Thanks to animal studies, we know a fair amount about what happens in the body when food is scarce. A lack of nutrients kick-starts a process called autophagy, in which cells break down and damaged or dysfunctional parts are

recycled and used as fuel. The thinking is that this system probably evolved to maximise the chances of surviving famine.

Autophagy happens at a low level in healthy cells but becomes less efficient as we age. Sluggish autophagy lets the inside of cells gunk up and has been linked to many age-related diseases including cancer, and to the ageing process itself. Some researchers believe that the rise in health problems like cancer and type 2 diabetes has a lot to do with the fact that many people no longer go hungry.

Although the initial findings came from research in mice, last year Longo and his colleagues published a study in around 100 people who either did the fasting mimicking diet for five days a month over three months, or continued with their normal diet for three months. The second group then tried the fasting diet. When people did the diet, they dropped body weight and fat, and ended up >

Don’t eat it

all at once

“ Our hunter-gatherer ancestors were adapted to periods of feast and famine”



with lower blood pressure and lower levels of a hormone called insulin-like growth factor-1 (IGF-1), which is thought to play a role in ageing and disease. They also had lower levels of inflammation markers and cholesterol, among other benefits.

For my little experiment, before I started the diet I underwent some blood tests, measuring levels of IGF-1, cholesterol and C-reactive protein (CRP), a marker of inflammation. I also had a body composition scan to measure any effects on my body fat at the Oxford Centre for Diabetes, Endocrinology and Metabolism. Fredrik Karpe, who runs the centre, is sceptical to say the least. “It is very important to critically investigate health claims for interventions giving great promises,” he says.

One crucial question is how long you need to fast to kick-start these processes. After all, we know that famines are seriously bad for our health. Unfortunately, the answer is unclear. In a recent review of the health effects of fasting, Benjamin Horne, at Intermountain Heart Institute in Salt Lake City, Utah, concluded that no research has yet identified a set line between fasting and starvation, and that it probably varies a lot depending on the body you have to start with.

Another effect of fasting is that the body starts to run out of glucose in the blood and glycogen stores in the liver, which causes a metabolic switch: the liver starts converting fats into ketone bodies for the muscles and brain to use as fuel, a process called ketosis. This is why fasting almost always causes weight loss of somewhere between 2.5 and 8 per cent. But how long you need to fast

hour,” he says. If you’re not eating during that time, “you do the math, it’s around 10 hours”.

Add exercise into the equation and the switch can happen even faster, says Mattson. A vigorous run can burn 100 calories in 10 minutes. Get your sports shoes on a few hours after your last meal and it won’t take long to hit ketosis, he says, leaving me wondering why I am sticking out a five-day fast instead.

Another claim about fasting that almost tempted me in the past was the cognitive effect. Fasters regularly boast about clearer thinking and improved focus. Ulijaszek observed something similar with modern-day hunter-gatherers. While foraging with the Wopkaimin of Papua New Guinea in the 1980s, he noted that they never started the day with breakfast because they preferred to be hungry while hunting. “They said it made them lighter on their feet, and more aware of their surroundings,” says Ulijaszek.

So far, though, no controlled studies have been done to investigate the link between fasting and cognition in humans, and the only hints about what might be going on come from mice. Mattson’s group found that switching to ketosis gives the brain a boost, stimulating the release of a chemical called BDNF, which promotes new connections between neurons and stimulates neurons to make more mitochondria, which generate energy. This could be the ticket to the mental clarity reported by fasters.

His team is conducting a randomised study in human volunteers to find out whether these brain changes and associated effects are seen in people, with results expected in early 2019.

Mental clarity certainly wasn’t something I experienced. My brain hit the wall early on day two and on most days during the fast I gave up trying to work and went back to bed. After day three my legs ached like I had the flu, apparently a sign of ketosis.

Shock results

It was difficult to believe that something that made me feel so awful could possibly be doing me good, especially since my test results from before the fast showed that I was already metabolically healthy. I had low levels of “bad” cholesterol, healthy blood sugar and fat levels and very low amounts of visceral fat – the stuff that sticks to our organs and which can be a risk factor for cardiovascular disease and diabetes. The body scan showed a fair amount of body fat (30 per cent), but nearly all concentrated on my hips

The evidence for the benefits

of fasting in healthy people is

controversial. But it may turn

out to work best when the body

is already struggling.

Animal studies suggest that

while healthy cells hunker down

during starvation, cancer cells

don’t, making them more

susceptible to chemotherapy.

The fasting mimicking diet

(see main story) was designed in

a bid to see if the same applies

to humans. Doctors weren’t keen

for their already thin patients

to fast, so Valter Longo at the

University of Southern California

in Los Angeles came up with a

very low calorie diet instead.

It is early days but initial results

suggest that fasting can reduce

the side effects of

chemotherapy, without reducing

its power to shrink tumours.

Longo is now trialling his diet

in people with multiple sclerosis

(MS) to see if it can prompt the

body to clear out the immune

cells responsible for the disease

and replace them with healthy

versions. Again, animal studies

look promising, but it remains to

be seen if it works in people too.

The evidence around diabetes

prevention is more unclear.

Some studies suggest that

fasting might reduce the

risk of type 2 diabetes, while

research presented at this

year’s European Society of

Endocrinology meeting warned

that intermittent fasting might

damage the pancreas and

increase the risk of the disease.

Either way, people who already

have the disease and are taking

insulin should steer well clear.

“If you do insulin plus fasting

or fast-mimicking diet, you

could actually kill someone,”

says Longo.

If you are unwell, you should

speak to your doctor before

embarking on a diet.

IN SICKNESS AND IN HEALTH?

before the switch to ketosis occurs is unknown. Longo says that it takes at least three days and that shorter fasts, such as the 5:2 diet, don’t last long enough to make it happen.

Mark Mattson at Johns Hopkins University in Baltimore, Maryland, who studies the effects of fasting on the brain, disagrees. “The liver holds maybe 700 calories-worth of glycogen and people’s general daily activity around the house burns maybe 70 calories an

Before After

Not so fastOur reporter underwent blood tests to measure markers of health and longevity before and after a �ve day fasting mimicking diet and saw minimal changes in most of them

*CRP is a measure of inlammation. IGF-1 is implicated in ageing and disease

Millimoles per litre (mmol/L)(unless otherwise stated)

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Fasting blood glucose

Fasting triglycerides

Fasting total cholesterol

HDL cholesterol

LDL cholesterol

non-HDL cholesterol

CRP* (mg/L)

IGF-1* (nmol/L)



does fasting truly offer a benefit beyond the fact you inevitably cut a few calories and lose a bit of weight?

Michelle Harvie, the researcher at Manchester University in the UK who came up with the 5:2 diet, told me that based on current research, we just don’t know. “Intermittent dieting is a proven method for weight loss… we don’t know benefits or harms for healthy weight or underweight people,” she says.

A serving of truth

Many of the original studies of fasting diets involved overweight volunteers. Even in Longo’s study of 100 healthy volunteers, two-thirds started with a BMI of over 25, making the vast majority overweight or obese. So, while their health markers such as body mass index, visceral fat and blood pressure were all significantly reduced after doing the fast three times over three months, it isn’t clear whether this can be explained by the simple fact that they lost weight. Fasting also tends to mean eating a lot less animal protein and fat, which have both been linked to cancer, so this might also be responsible for the effects seen in trials.

When a person is a healthy weight, their bodily clear-out functions work fine on their own, says Karpe. “Any normal physiological system, in a healthy, lean human being, eating well, exercising, doing what the body likes to do, all these things work. That’s why healthy people, who exercise and eat normal things, live longer than overweight people.”

Susan Jebb, a nutrition scientist at the University of Oxford, agrees: “I am not aware of any high-quality evidence relating to intermittent fasting among people who are not overweight.”

Time will tell whether humans benefit from fasting beyond weight loss. So I can’t help thinking that the wording printed on the box of ProLon that Longo sent me, which promises “rejuvenation from within”, is premature. We aren’t yet sure that the body clears out damaged cells and replaces them with something better.

For my money, armed with the knowledge that most of my body fat is stored away from my organs and my blood results are entirely within the healthy range, I think I will stick with my normal diet and take my chances. Yes, my body could probably handle less wine and chocolate, but going hungry in return for a payoff that may never materialise? Life’s too short. ■

Caroline Williams is a consultant for New Scientist

Five days of soup and little else each month

would be hard to swallow for many

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and thighs, a pattern that has been linked to a lower risk of heart disease and diabetes.

After five days of fasting, none of this had shifted. The body composition scan revealed that I had lost just over 1 kilogram in weight, 584 grams of which came from a loss of lean mass and only 168 grams from body fat. This was a bit of a shock – one selling point of the fasting mimicking diet is that it is supposed to target visceral fat while protecting lean mass. According to Longo, ketosis doesn’t target the visible wobbly bits, only fat around the organs. As I started off with little visceral fat, it instead targeted my lean mass, he says.

“From a global health perspective, I find it quite a negative outcome,” says Karpe. “Half of your change was muscle. The fat regions have not changed much at all. That’s not what you intended.”

Could it be that the lean mass loss was the result of autophagy? Mice put on Longo’s diet in middle age certainly seemed to have some kind of clear-out: their liver, heart and kidneys all shrank during the fast and they had a temporary cull in the numbers of some kinds of blood cells. All went back to normal within a few days of normal eating, heralded by an increase in markers of liver regeneration and tentative signs of muscle

regeneration. The assumption is that the decrepit cells that were removed were replaced by newer, shinier versions.

The evidence for autophagy and regeneration in human trials, however, is purely circumstantial. And we don’t know whether any new cells are healthier than what was lost. Longo concedes that this is something his team is still working on.

When it came to blood markers of health and longevity, my results were similarly unimpressive (see graph, left). The only marked difference was to the hormone IGF-1.

In the ProLon trials, volunteers saw a

significant reduction in IGF-1, which Longo says was still there three months after going back to a normal diet.

Whether this adds up to increased longevity, however, is less clear. Epidemiological studies have linked both low and high IGF-1 levels to early death, with high IGF-1 levels linked to increased cancer risk and low IGF-1 to cardiovascular disease.

Of course, my experiment of one isn’t very scientific, but it did get me wondering: for those of us who are healthy to begin with,

“ When people did the diet they had lower body weight, fat and cholesterol”



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THE Reykjanes peninsula juts out of the south-western tip of Iceland like a hitch-hiker’s thumb. Most visitors

glimpse it from a plane, as they swoop down onto the runway at Keflavík airport, or through the mist at the Blue Lagoon – a popular hot spring. It is an otherworldly landscape of rumpled volcanic rocks and stout cinder cones. The most common signs of life: tenacious mosses in varying shades of green, and the odd wandering sheep.

Here, the tectonic seam that runs along the bottom of the Atlantic, belching out new ocean crust between North America and Europe, runs aground. That’s what makes this place so attractive to people like Guðmundur Olaf Friðleifsson, chief geologist at Icelandic energy company HS Orka. Just a few kilometres beneath their feet, the staggering heat of a volcano bubbles away. All they have to do to harness its power is drill.

Iceland already has plenty of geothermal energy, but this project is different. Friðleifsson and his team are tapping into temperatures and pressures higher than anything we have used before, and building on our growing ability to extract more of Earth’s heat. What they are doing could help revolutionise geothermal energy and boost this overlooked source of renewable power to a prominent place in the global energy system. It has the potential to unlock unprecedented

amounts of energy, and make it accessible to places far from the volcanic fields of Iceland. It could make the dream of abundant geothermal power a reality.

So far, geothermal energy hasn’t taken off like other renewables. More than a century after humans started using Earth’s hot water and steam to produce power, geothermal provides less than 1 per cent of global electricity. There is no problem with supply: the depths of our planet still smoulder from its violent accretion and the slow burn of radioactive decay. The core is a searing 6000°C, and the heat contained in the upper 3 kilometres of the crust would be enough to meet the world’s energy demand thousands of times over.

Geothermal energy also sidesteps the problems that plague so many other clean sources of energy. It is always available, regardless of whether the wind blows or the sun shines. Alongside nuclear and hydropower, which have issues of their own, geothermal offers an attractive source of clean, reliable baseload electricity. But it has high start-up costs and has historically been restricted to Iceland and other hotspots. The challenge now is to increase the power and availability of geothermal energy so that it can truly compete.

The world’s first geothermal power generator was Italian, built in the verdant

Recent advances could let us crack the immense promise of geothermal heat to power our world. Julia Rosen reports

>

Steam rises from

the Reykjanes

peninsula in Iceland

Full steam ahead



hills of Tuscany in 1904. The seething, sulphurous hot springs of Larderello attracted Roman visitors millennia ago, and the Devil’s valley, as it is sometimes called, supposedly shaped Dante’s vision of hell. But others saw something else in the hissing steam: untamed energy. Today, 800 megawatts of power flow from the Larderello fields, supplying 10,000 residential and industrial consumers.

Yet humans are still just scratching the surface. Conventional technologies can only exploit geothermal energy in spots like Larderello, where heated water runs through a natural plumbing system easily accessible from the surface. But the Geothermal Energy Association, a US trade group, estimates that countries have developed just 7 per cent of the world’s hydrothermal potential.

Digging deeper

Over the past few decades, however, researchers have been exploring ways to extract even more heat, including in regions not blessed with ideal geology. This new approach, known as enhanced, or engineered, geothermal systems (EGS), can mean adding fluid to dry rocks to transport heat to the surface and generate steam, or fracturing impermeable formations so that liquid can flow through the hot rocks, heating up along the way. “It’s taking what nature gives you and figuring out how to make it work,” says Jeff Tester, a geothermal expert at Cornell University in New York.

EGS could crack open massive stores of geothermal heat. A 2006 report led by Tester found that, in the US alone, the technology could unlock 130,000 times as much energy as the country uses each year. Realistically, we will always need other sources of energy, and are likely to exploit just a fraction of geothermal’s potential. But, says Lauren Boyd at the US Department of Energy, EGS has another important advantage: it will make geothermal energy available outside existing hydrothermal systems. “It’s feasible everywhere,” she says.

The basic elements of EGS were first tested at an experimental site in New Mexico in the 1970s. Since those early days, “we have made leaps and bounds”, says Boyd. We know more about what’s going on underground, and have better drilling technology, some borrowed from advances in the oil and gas industry. But even so, engineers still face significant hurdles, says Boyd, and only a handful of commercial EGS sites operate today.

For one thing, creating fractures in controlled and predictable ways remains a

practical challenge, says Gioia Falcone, an engineer at the University of Glasgow, UK. Sometimes the cracks close up again under the immense pressure of the overlying rock. At other times, the rock cracks too much, and water flows too fast to heat up, she says.

EGS can also have more serious consequences. In 2006, a commercial project in Basel, Switzerland, triggered a magnitude-3.4 earthquake that rattled the city. No one was hurt, but it made many residents nervous – they knew a magnitude-6 quake had levelled the city in the Middle Ages. It isn’t the only case, either. In 2017, an EGS project in Pohang, South Korea, was the likely source of a magnitude-5.5 earthquake that caused $52 million in damage. Both projects were eventually shuttered.

There is no doubt that EGS, like mining, fracking for oil and gas, and disposing of waste water, can cause earthquakes, says Corinne Layland-Bachmann, an engineer at Lawrence Berkeley National Laboratory in California who studied the Basel case. However, Layland-Bachmann says the risk of a serious quake from geothermal production is low. She thinks incidents like those at Basel and Pohang can be avoided if developers choose EGS sites wisely and reduce injection rates if tremors begin.

But perhaps the biggest barrier to the approach has been economic. Since Tester’s report came out, the price of solar and wind energy has dropped, and cheap natural gas has flooded the market, making it hard for geothermal to expand, says Trenton Cladouhos at AltaRock Energy, a Seattle-based geothermal developer. “I’ve been working on EGS now for 10 years,” he says. “The market for geothermal just has been flat.”

So AltaRock and others have focused their efforts on a supercharged version of

geothermal instead. The idea they are pursuing has its roots in a series of accidents from the 1980s, when geothermal engineers unexpectedly encountered super-hot conditions. The first incident happened at Larderello, where a well struck 380°C water just shy of 4 kilometres down. The drillers were totally unprepared for this heat, as were the materials they had used to make their well. They abandoned it when it became clear the casing wouldn’t hold. Another hole, drilled nearby a few years later, hit the same reservoir and blew out in a massive explosion of steam.

In 1988, something similar happened in Iceland. But Friðleifsson, who had recently completed his PhD on another Icelandic volcano, wasn’t surprised by the find. He also realised that, if researchers could figure out how to manage these fluids, they could capitalise on a geothermal bonanza.

That is because, above 374°C and 221 bars of pressure, water transforms into a supercritical fluid. As the temperature and pressure rise, says Friðleifsson, water gets lighter and steam gets heavier until they become one phase. And it’s a totally different beast.

Supercritical water at 400°C contains five times as much energy as water at 200°C in a typical geothermal well. It also transfers energy twice as efficiently and has a lower viscosity, flowing out of the ground more easily. In 2003, Friðleifsson and Wilfred Elders, now an emeritus professor at the University

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2.5GWEurope’s 2016 geothermalpower capacity

vs

6500GWIts potential power capacity with enhanced geothermal systems technologySOURCES: EUROPEAN GEOTHERMAL ENERGY COUNCIL, DOI.ORG/F5TNQ3



of California, Riverside, who together lead the geothermal project at Reykjanes, calculated that a well producing supercritical fluid could generate ten times more energy than a conventional one.

Cladouhos says that could make the economics of geothermal work out for companies like his. It costs more to drill to supercritical depths, but the increased energy production should more than compensate, he says. “EGS is really difficult to do, so you might as well do it in an area where you know the economics are going to be helpful.”

No one has been able to demonstrate the increased payout of supercritical geothermal so far, but in Iceland they are getting close. In 2009, Friðleifsson and Elders’s team reached supercritical conditions when it accidentally drilled into a magma chamber at the Krafla volcano. For two years, that well produced a jet of superheated steam, but then a valve failed and it had to be sealed.

The Icelandic group then began the project at Reykjanes, where they drilled a well 4.6 kilometres down to access fluids as hot as 600°C. For the past year, engineers have been pouring cold water down the well, which cracks the rocks and is sometimes used in EGS to increase a reservoir’s permeability. Now, the team is just waiting for the well to heat up again before they start testing it.

Meanwhile, a new supercritical well has been completed at Larderello. “The first time,

we met supercritical conditions by chance,” says Sandra Scalari, at Enel Green Power, which runs the Larderello site. But this time, she says, “it was intentional”. There are also supercritical projects planned in Japan, Mexico and New Zealand, and AltaRock is looking for funding to deepen an existing well at Newberry volcano in Oregon. The rest of the world is catching up, says Friðleifsson. “The only difference between us and them is that Iceland is in the lead.”

Like at Reykjanes, these projects will probably use EGS, and share the same risks and challenges – plus others associated with working in extreme conditions. “The drill bits basically just start to deform and melt,” says Cladouhos. After that, engineers must figure out how to line the wells. Standard casing materials aren’t designed for such high temperatures, or for the corrosive fluids that bubble up from the depths. These eat away at valves and cement coatings, which expand and contract in the changing temperatures, risking blowouts. Finally, the standard electronics used to measure conditions in the well just get fried. “The equipment is usually made for the oil and gas industry,” says Enel’s Massimo Luchini, and it was never designed to handle such intense heat.

There are geological uncertainties too, says Thomas Reinsch, an engineer at the Delft University of Technology in the Netherlands. The tools usually used to probe Earth’s depths – like tracking how seismic waves move through the crust – have not been calibrated for rocks at extreme temperatures and pressures, because it is hard to recreate such conditions in the lab. That means the results can be hard to interpret. “We don’t know what kind of geology is down there,” says Reinsch. “We are drilling basically into the dark.”

All in all, developing supercritical geothermal is a monumental challenge.

But Friðleifsson is optimistic the teams will ultimately prevail. “You can send a rocket to the moon,” he says. “Compared to that, it’s a piece of cake to drill into the ground.”

For now, scientists and energy companies are mostly pursuing EGS and supercritical geothermal in places where it is relatively easy to reach the temperatures they need – like Iceland, Italy and the American West. But eventually, many hope these techniques will allow geothermal energy to spread.

For the right price, EGS could make geothermal energy available across much of the world. Even in places with cooler crust, it could be used to extract heat for buildings, says Tester. And supercritical geothermal could unleash enormous energy reserves in volcanic areas around the world, says Luchini. “There is a big potential.”

Ample supercritical resources in one place could even be enough to power surrounding countries, says Falcone. There has been talk, for instance, of Iceland supplying power to 1.6 million homes in the UK. “Electricity is transportable,” she says.

But could high-powered supercritical projects ever be feasible in all areas? Reaching such conditions in places with cooler, thick crust, like the US Midwest or eastern Europe, would require boring through more than 15 kilometres of crust, 3 kilometres deeper than any drill has previously gone. “I wouldn’t say that we’re going to see supercritical geothermal developed in Kansas in the near future unless you have some magical way of really reducing the cost of really deep drilling,” says Elders.

But Cladouhos never says never. Engineers are exploring novel drilling methods, using energy waves, high-pressure fluid jets or lasers instead of metal drill bits. He is holding out hope that a breakthrough will make supercritical geothermal ubiquitous. “Maybe the 20-year plan would be supercritical EGS anywhere,” he says.

Even if Cladouhos’s dream doesn’t come to pass, the potential benefits of supercritical wells could still help geothermal become a major global player, says Falcone.

That future may not be so far off. Friðleifsson’s team plans to get the Reykjanes well flowing in early 2019, eventually linking it to a nearby power plant to make the first commercial supercritical site in the world. Even if someone beats them to it, says Friðleifsson, a geothermal revolution is coming. “It is not a question of if, but when. ■

Julia Rosen is a journalist in Portland, Oregon

Iceland’s Reykjanes power

plant hopes to harness

Earth’s deep heat

5MWTypical power output of a geothermal well

vs

50MWPredicted output of a “supercritical” wellSOURCE: DOI.ORG/FMPP3D



CHEMISTS have a unique power to manipulate matter. Imagine any arrangement of atoms you like and a

chemist will have a good shot at stitching them together. Over the decades, their round-bottomed flasks have helped bring all sorts of new compounds into being, from dazzling pigments to miracle pills and wonder materials. But they don’t come easy, not least because chemists must do it all backwards.

The tried-and-tested method for planning how to create a sophisticated molecule starts where you would like to end up. You draw out

The disassembly lineMaking new molecules requires artful reverse engineering. Now we can

do it at the touch of a button, says James Mitchell Crow

That is why a few chemists think the quickest path to molecules more wondrous than ever lies in taking themselves out of the equation.

Most of the biological world is built of organic, or carbon-containing, molecules. From hormones to vitamins to poisons, organic chemists have long tried to both divine their structures and find ways to make them in the laboratory.

In the middle of the 20th century, chemists generally tried to synthesise new compounds by starting from structures that looked similar to the target. That yielded handy compounds

the web of connected atoms you want to make, then pick it apart, working backwards to plot out a series of reactions that, if performed in the reverse order, will get you to your goal.

It is a simple, old and indispensable idea that won its inventor a Nobel prize. Plenty of the last century’s finest drugs have chemical structures so fiendishly complicated that they could never have been made without a logical reverse engineering.

Yet with thousands of possible ways to make compounds of even middling complexity, it is tough for humans to spot the best routes.



right enough, from synthetic versions of penicillin to the progesterone hormone used in the first birth control pill. But there was a large and exotic landscape of potentially useful compounds that no one had the faintest idea how to produce in the lab.

In the 1960s, the Harvard University chemist Elias Corey decided to make the planning of syntheses more logical. He realised a good way to do that would be to work backwards, which led to the name retrosynthesis.

Take a blank piece of paper and draw the target molecule at the top. Examining the bonds holding it together, the chemist will pick one and break it. Choosing the right bond is where the years of training come in. The bond you break on paper has to be one you think you could make in the laboratory, in what would be the final step of the synthesis.

First bond disconnected, you go again. Step by step, you walk your molecule backwards, stripping away complexity until you reach a structure so simple you can buy it (see diagram, page 40). A particularly fiendish structure might take 30 steps to deconstruct to this point.

“You don’t work back to a specific precursor, just to simpler and simpler structures,” says Michael Sherburn, a synthetic organic chemist at the Australian National University in Canberra. “If you do it without bias, then you end up at starting materials you perhaps wouldn’t have considered.” It is like planning

the ascent of a never-before-scaled mountain. Starting from the peak, reverse-plotting the route eventually reveals the base camp from which an ascent has the best chance of success.

The moment of truth comes when you crack open a bottle of your starting chemical. Not every route planned on paper works first time, because this is virgin chemical territory. Still, retrosynthesis has become routine for planning the most difficult chemical targets (see “Totally synthetic”, page 41).

Few chemists go back and read Corey’s original papers on the subject, but if you do

there’s a surprise, says Matthew Todd, chair of drug discovery at University College London. “I thought Corey was codifying a very human activity, but right from the get-go his explicit aim in developing retrosynthesis was to tell a computer how to do it,” says Todd.

Corey and his team even developed such a program, called LHASA for Logic and Heuristics Applied to Synthetic Analysis. But it wasn’t a genuinely useful tool, being hamstrung by the limited speed and memory of 1970s computers.

Computers have come a long way since then. For Todd, a key moment came in 1997 when chess world champion Garry Kasparov lost to IBM supercomputer Deep Blue. “We often talk about chess and organic synthesis as being similar,” says Todd. Both involve strategically plotting moves. “The fact one area had fallen to a computer made me think about the other.”

When Todd eventually decided to write a paper on the subject in 2005, he was startled at how little had been done since Corey’s work on LHASA. He ended up speaking with Deep Blue’s developers, who told him that formidable computing power wasn’t >

“ Chess and chemistry are very similar. They’re both about plotting moves”

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enough. Chess has so many possible permutations that even a potent computer can’t crunch through them all. The essential ingredient of Deep Blue’s success was the software that encoded the heuristics of chess, the rules of thumb that allowed it to quickly discard bad moves.

At the time, no one was interested in encoding equivalent rules for chemical synthesis. That’s partly because those rules are extremely complex. In chess, there are tens of potential moves from any position. In chemistry, the number of possible transformations for a single step of a synthesis can range from about 80 to several thousand. Even using the conservative estimate of 100 choices per step, a 15-stage synthesis becomes a tree of possibilities with 100 million billion branches. As one industry insider put it to Todd, it was cheaper to pay consultancy fees and get top academics to do the retrosynthesis manually.

But what if we could get machines to teach themselves the rules? That is the promise of the burgeoning field of machine learning. Let’s say we want an algorithm to find films that certain types of people will enjoy. Simply give the algorithm a long list of films and information about them, together with a list of the people who liked them. The machine can then learn to recommend films with certain characteristics to people who like those qualities.

These algorithms are not smart as such, they only learn to reproduce relationships discovered in the training data. The effects can be tremendous, however. An algorithm created by artificial intelligence firm DeepMind taught itself to play the strategy board game Go better than any human.

The most promising attempt at machine

learning retrosynthesis comes from Mark Waller at Shanghai University in China and Marwin Segler at the University of Münster in Germany. They developed a neural network, a computing system inspired by the brain, that taught itself the rules of organic chemistry by sifting through a major database of reactions. The program then predicted routes to moderately complex structures that typically required six synthetic steps to make. Although the syntheses were not tested in the lab, Waller and Segler asked chemists to distinguish the computer syntheses from human efforts in a double-blind test. They couldn’t.

The trend for artificial retrosynthesis is catching on with big players, including the publishing giant Wiley. It has a commercial database called SciFinder that chemists use to find recipes for individual reactions. Recently, the firm added a computer-aided tool called

ChemPlanner to this package that suggests whole synthetic routes.

Yet there is no published evidence as to how impressive ChemPlanner’s abilities are. And for their part, Waller and Segler say their system is not ready to tackle the most prized and challenging targets, such as “natural products”, the often medicinally useful and intricately structured molecules isolated from natural sources such as plants or microbes.

One man who hopes he can do better is Bartosz Grzybowski at the Ulsan National Institute of Science and Technology (UNIST) in South Korea. He began his career studying the physics of chemical systems, not cooking up molecules. But, intrigued by the

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The remaining molecule of interest now contains an NH2 group, which is hard to add to a carbon ring like this, so it is converted into an NO2 group

Take an imaginary slice through a carbon-nitrogen bond in a molecule of paracetamol, yielding two simpler molecules

NO2 groups are easy to add to carbon rings, so the bond to that part can be broken

Retrosynthesis in actionWhen chemists identify a promising drug, they must then work out how to make it. They use an approach called retrosynthesis, which deconstructs the target into simpler, starting materials. Here’s how it could work for paracetamol

Paracetamol Phenol (a cheap starting material)

The �nal step gets us to what would be the starting material of the forward synthesis

Computers learned the rules of chess.

Now they have done the same for

synthetic chemistry

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challenge of artificial retrosynthesis, he began exploring the mathematics that would allow a computer to efficiently navigate one of those vast trees with millions of branches. People were mildly bemused when, from 2005, his hardcore maths papers started turning up in chemistry journals, Grzybowski recalls. But it was an essential first step.

From there, Grzybowski encountered the same problem that Todd had identified: he needed a way to help his program quickly discount bad moves. He investigated feeding it a database of reactions, but “the quality of chemistry you get out is pretty pathetic”, he says. So he and his team took a path others had written off and spent years teaching the program 50,000 rules describing why bonds change as they do.

Pulling the rules together took a long time, but by 2012, he had shown that his fledgling program, Chematica, worked in principle. But coming up with a recipe for a molecule is one thing. “Unless you cook something, it doesn’t exist,” says Grzybowski.

He began negotiating to sell the software to chemical supplies firm MilliporeSigma in 2017. The company wanted to test the program

on molecules its chemists could produce only in low yield or not at all. The team went on to check eight Chematica retrosyntheses, including one of a natural product. They all worked and the sale went through, with the program being renamed Synthia.

It is a landmark result. But despite the potential, not everyone is as enthusiastic as Grzybowski.

In fact, the artificial retrosynthesis concept has proved polarising. “Some believe synthesis is mainly about artistry, and that human imagination and intellect, creativity and knowledge, can never be beaten by a computer,” says Sherburn. But then, they said that about chess. Chemistry may be more complicated for algorithms to master, but that day could come. In the nearer future, Sherburn says, he can imagine using programs as he would a colleague, to get new ideas or ask for advice.

Perhaps it won’t just be chemists asking for advice. A few years ago, Grzybowski warned that his program could make it easier for terrorists to make toxic chemicals. But in reality it won’t help much. All the program does is plan a synthesis. It still takes a highly trained chemist with specialist equipment to realise it.

Fears of chemists losing their jobs to AIs are probably also overblown. It is more likely that synthesis will become like playing advanced chess where grand masters face off armed with laptops, says Todd. The computer checks for blunders, which are just as important to avoid in synthesis as in chess. “You want to make sure you’re not missing something,” he says. Synthia proved particularly adept at spotting reactions in which three or more simple molecules zip together in one go.

Even if some see Grzybowski’s work as removing the artistry from chemistry, he can at least take comfort that his work in a sense completes retrosynthesis and brings it back to Corey’s grand vision to drive chemistry forward – by doing it backwards with a computer. ■

James Mitchell Crow is a science writer based in Melbourne, Australia

Totally synthetic

Chemists whip up all manner of useful molecules, many of which are efective drugs. Through the years, we’ve scaled more and more diicult synthetic peaks

1964LONGIFOLENE

Chemist Elias Corey at Harvard University came up with retrosynthesis, a method of logically planning how to stitch together chemicals. One of the first molecules he tried it on was longifolene, a component of pine resin, and one of the aromatic molecules found in lapsang souchong tea, which is smoked over pine fires. These days it is not considered difficult, but at the time no one had synthesised it before.

1977 L-DOPA

Starting in the 1950s, thalidomide was prescribed as a cure for morning sickness. It was a mixture of two mirror-image forms, like right and left hands. Doctors didn’t know at the time, but one of these forms caused birth defects. That led chemists to find ways of making the mirror-image forms separately. William Knowles was the first to find a way of mass producing just one of these forms. It was the amino acid derivative L-dopa, used to treat Parkinson’s disease. Since then, such methods have become crucial in drug manufacturing.

1989PALYTOXIN

Made by corals, palytoxin is the second most toxic non-protein we know of. Just 3 micrograms is thought to be enough to kill a human. Its production was desired because its huge size and complexity made it the Mount Everest of chemical synthesis. Whereas thalidomide came in two stereoisomers, palytoxin has 1021, only one of which is the correct structure. It was built in eight parts by a team led by Yoshito Kishi at Harvard University before they were all connected together.

1994TAXOL

This chemotherapy drug was first synthesised by two research teams, led by Kyriacos Nicolaou and Robert Holton, within a month of each other. Before that, the drug, also called paclitaxel, was harvested from the sap of rare Pacific yew trees, making it scarce and costly. There are stories from the 1990s of the relatives of people with cancer going into forests looking for the trees. Synthesis helped lessen pressure on the species.

2017RESINIFERATOXIN

Resiniferatoxin is another poisonous molecule. At low doses, it binds a protein found in nerves and dials down chronic pain. Synthesising it was daunting, because it contains several rings of atoms fused together. These rings are hard to build and chemically sensitive, so they can easily split apart.

It was prepared in 44 steps in 1997, but renewed interest in the drug prompted Masayuki Inoue of the University of Tokyo to devise a shorter way. There is still a way to go before the drug can be affordably manufactured.

“ Coming up with a molecule recipe is one thing. Unless you cook it, it doesn’t exist”



THIS is a bittersweet moment. The publication of my father’s last book, Brief Answers to the Big Questions, is

a triumph in many ways. It is a summation of his career, both in science and in public advocacy on a range of issues that he cared about deeply. It is the fruit of decades of thought and scientific enquiry, as well as hard work, his mastery of technical communication and his experience on the public stage.

From examination of the nature of life itself to exploration of the most mysterious regions of space, the book is a hymn to rational scientific enquiry. Famously, my father said of his 1988 bestseller A Brief History of Time that he wanted to see it on airport shelves. He certainly achieved that ambition. I hope this book will fulfil it too.

But this is also a time of great sadness for me. The beginning of this book’s journey marks a full stop. This is the “last” book. While my father’s legacy will, I hope, live on in a myriad of different ways, I have to accept finally that he himself has gone.

For the past six months, that hasn’t seemed real to me. So much of what we have talked about, thought about, organised, celebrated and mourned since his death has had my father as the central figure. It has been as though he were still there, still the gravitational force holding us all in orbit. Only now do I have the sense that he is departing, leaving us for the final time.

I went to his house the week before last and found it deeply moving. I cried over a table cloth that I bought for him in New Delhi, while I was on tour in South Asia with one of the five children’s books we wrote together. Odd though it seems, technically I am my father’s most prolific co-author. Together, we created a series of adventure novels for kids that read like escapist fantasy, except that the science in all of them was accurate and up to date.

As my father liked to say, “Where Harry Potter has magic, we have science”. I vividly remember reading him an extract I had just written for George’s Cosmic Treasure Hunt, which featured a character with a startling similarity to his own mother. He laughed so much he nearly fell off his chair. Those were good times.

I admired my father all my life, but never so much as in the final months of his life, when he fought like a true soldier but let go at the end with grace. Born on the anniversary of Galileo’s death, my father died on Einstein’s birthday. This final flourish somehow seemed so typical of him, an awesome poetry that left us in bewildered wonderment through our tears.

It feels like no coincidence that his final scientific paper, detailed in this book, concerns symmetry. In the chapter “What is inside a black hole?”, my father discusses work he did with Malcolm Perry, Sasha Haco and Andy Strominger on “supertranslations”, infinite collections of symmetries found in areas of space-time far from black holes. These might help resolve the black hole information paradox, the puzzle of what happens to the information entering a black hole, which has generated arguments among scientists for more than 40 years (see “Do black holes eat information?”, page 45).

Like many other problems on the cutting edge of physics that my father worked on, this remains unresolved. As his lifelong best friend Kip Thorne says in his introduction to the book, “Newton gave us answers. Hawking gave us questions. And Hawking’s questions keep on giving, generating breakthroughs decades later.” If Brief Answers is the end, then it is a comfort that the big questions live on. ■

Lucy Hawking is a novelist and educator based in London. See overleaf for a review of Brief

Answers to the Big Questions, and an extract

Memories of my fatherAs Stephen Hawking’s �nal book is published, his daughter Lucy Hawking relects on its meaning for her

Lucy Hawking and her

father in 2015. He died

on 14 March this year

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and environmental degradation, his contempt for Trump and the regressive aspects of Brexit, and (albeit not in this book) his championing of the UK’s National Health Service, made you glad to have Hawking on your side.

A common danger with such collections is repetition. But the recurring and familiar passages are themselves quite revealing, for they show Hawking curating his image: the boy always taking things apart but not always managing to put them together again, the man who told us to “look up at the stars and not down at your feet”.

There’s no doubt that Hawking cared passionately about the future of humankind and the potential of science to improve it. His advocacy resembles the old-fashioned boosterism of H. G. Wells in later life, tempered by an awareness of the dire potential of technologies in

that the physicist would have preferred the film to have had “more physics and fewer feelings”.

I approached this book with some trepidation. You know he won’t go wrong with cosmology, relativity or quantum mechanics, but when Hawking stepped outside that comfort zone the results were often touch and go.

The scientific essays included in this book supply Hawking’s Greatest Hits: his work with mathematician Roger Penrose on gravitational singularities and their relation to the big bang; his realisation that black holes will emit energy (Hawking radiation); his speculations about the origin of the universe in a chance quantum fluctuation; the debate (still unresolved) about whether black holes destroy information.

Hawking, as fellow cosmologist and long-time friend Kip Thorne outlines in his introduction, helped to integrate some of the central concepts of physics: general relativity, quantum mechanics, thermodynamics and information theory. It is a phenomenal body of work.

Sometimes there is a plainness to his prose that is touching even when it sounds like a self-help manual: “Be brave, be curious, be determined, overcome the odds. It can be done.” His plea for inspirational teaching, his concerns about climate change

Hawking was first to suggest that

black holes might emit energy

Brief Answers to the Big Questions by Stephen Hawking, Hodder & Stoughton

MOST people as famous as Stephen Hawking face forensically intimate scrutiny. But in its way, Hawking’s personality was

as insulated as the Queen’s, impermeably fortified by the role allotted to him.

There’s a hint in Brief Answers that he knew this: “I fit the stereotype of a disabled genius,” he writes.

But his easiness with this idea made me uneasy. While it was delightful to see how in everyday life he demolished the laziness that links physical with mental disability, he did so only by personifying the other extreme. The unworldly intelligence, the wry sense of humour, his tremendous resilience against adversity – such a mind in such a body! And then of course, there was that computerised voice (another part of his armour).

It perhaps suited Hawking that the media were content with the cliché – he gave little impression of caring for the touchy-feely. In the foreword to Brief Answers, Eddie Redmayne, who played Hawking in the 2014 biopic The Theory of Everything, reminds us

An ordinary geniusStephen Hawking’s last book reveals the mind and the man, says Philip Ball

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the wrong hands. One of the most striking

features of this book, however, is the lack of extracurricular context, from, say, art, music, literature, philosophy. In some pieces, this exposes gaps – for example, when Hawking begins an essay called “Is there a God?” with “people will always cling to religion, because it gives comfort, and they do not trust or understand science”. God, he tells us (as no theologian ever did), is all about explaining the origin of the universe.

And on what grounds does he claim that most people define God as “a human-like being, with whom one can have a personal relationship”? Even if true, most people’s notions of a molecule also bear scant resemblance to what well-informed folk say on



the matter, but Hawking would not have been happy with that.

There’s a sloppiness to the history too, even in science: for instance, he perpetuates the myth that Max Planck postulated the quantum to avoid the “ultraviolet catastrophe” of black-body radiation. Planck never mentioned it in his proposal.

There’s worse. “People might well have argued that it was a waste of money to send Columbus on a wild goose chase. Yet the discovery of the New World made a profound difference to the Old. Just think, we wouldn’t have had the Big Mac or KFC,” he writes, the joke perhaps hiding a reluctance to probe more deeply. The remark appears in a defence of space exploration, but he shows no

more inclination to examine the real reasons for the space race than to reflect on the realities of Columbus’s mission.

But this is all, in a sense, unfair. Hawking was a great scientist who had a remarkable life, and in another universe, without motor neurone disease (well, he did like the “many worlds” interpretation of quantum mechanics), we would have no reason to confer authority on his thoughts about all and sundry. We would not deny his right to ordinariness, and would see his occasional arrogance for no more or less than it was.

There is every reason to believe Hawking enjoyed his fame, and that’s a cheering thought. That we seek to put him on a pedestal is our problem, not his. We should celebrate his extraordinary achievements, both personal and scientific – but to paraphrase Brecht’s Galileo, unhappy is the land that needs a guru. ■

Philip Ball is a science writer. His latest book is Beyond Weird (Bodley Head)

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Do black holes eat information?

In Brief Answers to the Big Questions, Stephen Hawking attempts a new answer to this decades-old problem, the black hole information paradox

“ He cared passionately about the future of humankind and science’s potential to improve it”

Suppose there was no gravity and space-time was completely flat. This would be like a completely featureless desert. Such a place

has two types of symmetry. The first is called translation symmetry. If you moved from one point in the desert to another, you would not notice any change. The second symmetry is rotation symmetry. If you stood somewhere in the desert and started to turn around, you would again not notice any difference in what you saw. These symmetries are also found in “flat” space-time, the space-time one finds in the absence of any matter.

If one put something into this desert, these symmetries would be broken. Suppose there was a mountain, an oasis and some cacti in the desert, it would look different in different places and in different directions. The same is true of space-time. If one puts objects into a space-time, the translational and rotational symmetries get broken. And introducing objects into a space-time is what produces gravity.

A black hole is a region of space-time where gravity is strong, space-time is violently distorted and so one expects its symmetries to be broken. However, as one moves away from the black hole, the curvature of space-time gets less and less. Very far away from the black hole, space-time looks very much like flat space-time.

Back in the 1960s, Hermann Bondi, A. W. Kenneth Metzner, M. G. J. van der Burg and Rainer Sachs made the truly remarkable discovery that space-time far

away from any matter has an infinite collection of symmetries known as supertranslations. Each of these symmetries is associated with a conserved quantity, known as the supertranslation charges. A conserved quantity is a quantity that does not change as a system evolves. These are generalisations of more familiar conserved quantities. For example, if space-time does not change in time, then energy is conserved. If space-time looks the same at different points in space, then momentum is conserved.

What was remarkable about the discovery of supertranslations is that there are an infinite number of conserved quantities far from a black hole. It is these conservation laws that have given an extraordinary and unexpected insight into process in gravitational physics.

In 2016, together with my collaborators Malcolm Perry and Andy Strominger, I was working on using these new results with their associated conserved quantities to find a possible resolution to the information paradox. We know that the three discernible properties of black holes are their mass, their charge and their angular momentum. These are the classical charges that have been understood for a long time. However, black holes also carry a supertranslation charge. So perhaps black holes have a lot more to them than we first thought. They are not bald or with only three hairs, but actually have a very large amount of supertranslation hair.

This supertranslation hair might encode some of the information about what is inside the black hole. It is likely that these supertranslation charges do not contain all of the information, but the rest might be accounted for by some additional conserved quantities, superrotation charges, associated with some additional related symmetries called superrotations, which are as yet, not well understood. If this is right, and all the information about a black hole can be understood in terms of its “hairs”, then perhaps there is no loss of information. These ideas have just received confirmation with our most recent calculations. Strominger, Perry and myself, together with a graduate student, Sasha Haco, have discovered that these superrotation charges can account for the entire entropy of any black hole. Quantum mechanics continues to hold, and information is stored on the horizon, the surface of the black hole.

The black holes are still characterised only by their overall mass, electric charge and spin outside the event horizon but the event horizon itself contains the information needed to tell us about what has fallen into the black hole in a way that goes beyond these three characteristics the black hole has. People are still working on these issues and therefore the information paradox remains unresolved. But I am optimistic that we are moving towards a solution. Watch this space.



DON’T MISS

Read Spanning science and politics,

discoveries and global epidemics,

Nine Pints: A journey through the

money, medicine, and mysteries

of blood (Metropolitan) by Rose

George should get any science

fan’s heart pumping.

Listen On 23 October at 11.30am BST, the

BBC World Service’s In The Studio

follows Cuban artist and activist

Tania Bruguera as she installs a

vast heat-sensitive artwork in the

Tate Modern gallery in London.

SubscribePodcast Here We Are from

Starburns Audio features comedian

Shane Mauss’s journey of discovery.

In the Evolution of Alcohol episode,

Mauss has an IPA-fuelled chat with

microbiologist Kevin McCabe about

the genetic origin-story of yeast.

VisitAll I Know Is What’s On The

Internet, an exhibition opening

26 October at The Photographers’

Gallery, London, sees artists

exploring our algorithmically

driven culture.

WatchJohn Carpenter’s paranoid sci-fi

classic They Live (pictured below)

is re-released in UK theatres on

26 October in a 4K restoration.

You’ll never look at adverts in the

same way again. Or sunglasses.

Or people, come to that.

Red Moon

by Kim Stanley Robinson, Orbit

THE moon is so hot right now. No, not literally. It’s the 50th anniversary of the moon landings next year, and with it there is a flurry

of excitement around our only natural satellite that almost makes up for 50-odd years of neglect.

In September, SpaceX announced that it plans to send a paying customer on a flight around the moon as early as 2023. China is launching the Chang’e 4 robot to the far side of the moon in December, and next year Chang’e 5 will collect rocks and return them to Earth.

So Kim Stanley Robinson’s new novel is timely, to say the least. Set mostly on the moon in 2047, Red Moon describes burgeoning lunar settlements, mostly built by

the Chinese. The book opens with an American quantum engineer, Fred Fredericks, chatting with a famous Chinese travel writer, Ta Shu, en route to the moon. Fredericks is delivering an ultra-secure quantum telephone to the Chinese Lunar Authority chief, but the latter drops dead soon after the two meet.

Framed for the murder, Fredericks, along with Chan Qi, the pregnant daughter of a top Chinese politician, goes on the run, shuttling between the moon and China to elude capture.

Robinson is famous for the scientific detail and plausibility of his novels. His award-winning Mars trilogy describes the settlement of the Red Planet from the first footsteps on the surface to the terraforming of the planet centuries later. Whether he is imagining the richness of Neanderthal and Cro-Magnon culture in southern France 30,000 years ago, as he did in Shaman (2013), or the expansion of human society across the solar system, as he did in 2312

CULTURE

Red sky at nightA detailed vision of lunar living sends Rowan Hooper into orbit

The future’s bright, and Chinese,

in Kim Stanley Robinson’s new novel

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(published 2012), Robinson has an impressive range.

In Red Moon, he turns his attention to all things lunar, but this is as much a primer on China as a 21st-century superpower as it is a description of lunar living.

Ta Shu (who is obviously a stand-in for Robinson’s own musings) contemplates the reasons that China has achieved lunar domination: “Money needs to be spent to become wealth,” he says.

Ta Shu notes that the global economy has been around far longer than most people realise, and that China has been building up wealth for centuries. Most of the Roman silver coins ever minted ended up in China, we are told. The Yongle emperor in the 15th century ordered the construction of what is now Beijing even though the imperial capital was well established in Nanjing, and he did it, we are told, because his coffers were overflowing with cash.

The Great Wall was a similarly gigantic infrastructure project, partly launched to use up surplus wealth, as was the Beijing-Hangzhou Grand Canal, the oldest and longest artificial river in the world. Beijing, the Grand Canal, the Great Wall – and now the moon. Robinson builds such a plausible case for Chinese domination on the moon that in parts his novel reads like a history.

Red Moon’s depiction of its characters’ inner lives feels slightly underpowered, but Robinson has once again created a deeply realised world that feels more like a peep into our future than a work of fiction. I only hope we are as established on the moon by 2047 as he describes. ■


TENURE-TRACK ASSISTANT PROFESSORPHYSICAL CHEMISTRY

Faculty of Arts and Sciences Department of Chemistry and Chemical Biology

Position Description: Candidates are invited to apply for a tenure-track assistant professorship in physical chemistry, broadly defined, including experimental and theoretical research in areas such as but not limited to atomic and molecular physics, biophysical chemistry, condensed matter, quantum science and ultrafast spectroscopy. The appointment is expected to begin on July 1, 2019. The tenure-track professor will be responsible for teaching at the undergraduate and graduate levels. We are seeking candidates who have an outstanding research record and a strong commitment to undergraduate and graduate teaching.

Basic Qualifications: Doctorate or terminal degree in chemistry or related discipline required by the time the appointment begins.

Additional Qualifications: Demonstrated experience in teaching is desired.

Special Instructions: Please submit the following materials through the ARIeS portal (https://academicpositions.harvard.edu/8371). Applications must be submitted no later than October 15, 2018.

1. Cover letter2. Curriculum Vitae with publications list3. Teaching statement (describing teaching approach and philosophy)4. Outline of future research plans5. Names and contact information of 3-5 references. Three letters of

recommendation are required, and the application is complete only when all three letters have been received.

6. Selected publications

Contact Information: Susan M. Kinsella, Search Administrator, Department of Chemistry and Chemical Biology, Faculty of Arts and Sciences, Harvard University, 12 Oxford St., Cambridge, MA 02138. Phone: 617-496-4088. [email protected]

Harvard is an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, disability status, protected veteran status, gender identity, sexual orientation, pregnancy and pregnancy-related conditions, or any other characteristic protected by law.have been submitted.

Professor of Chemistry

he Department of Chemistry of the University of Wisconsin-Madison is accepting applications for multiple positions at the tenured and tenure-track level, beginning August 2019. We seek outstanding candidates with research interests in all areas of chemistry.

Ph.D. in Chemistry or related ield is required prior to the start of the appointment. Area of specialization within chemistry is open. Candidates for the Assistant Professor title must have demonstrated potential for internationally recognized research in his/her ield of specialization. Tenured candidates must have demonstrated excellence in scholarly research, teaching, and service. he successful candidates will be expected to teach chemistry courses at the undergraduate and graduate level. Mentoring of graduate and undergraduate students is required, as is the development of an internationally recognized scholarly research program. Professional and university service are also required.

Please go to https://academicjobsonline.org/ajo/jobs/11873 to view the posting and begin the application process. Application materials including cover letter, current CV, teaching statement, research experience summary, and a concise description of research plans will be required for all applicants. Applicants will also be asked to provide the names and contact information for three professional references. To guarantee full consideration, applications must be received by October 18, 2018. However, applications will be accepted until all positions are illed.

he University of Wisconsin-Madison is an equal opportunity airmative action employer. Women and minority candidates are especially encouraged to apply. Unless conidentiality is requested in writing, information regarding the identity of the applicant must be released on request. Finalists cannot be guaranteed conidentiality. A criminal background check will be required prior to employment.

The Department of Neuroscience at Yale University seeks to hire faculty in

any area of neuroscience, with a preference for candidates who use neuronal

or systems level analysis to investigate circuits, behavior or cognition in

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Emphasis will be placed on recruiting at the level of Assistant Professor, but

excellent applicants at Associate Professor level will also be considered. We

seek candidates with an exceptional track record, potential for outstanding

future achievements, and a wish to participate in a dynamic and recently

expanded neuroscience community at Yale that includes the Kavli Institute for

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Candidates must hold a Ph.D., M.D., or equivalent degree. Please send a

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plan (strictly limited to 2 pages), and arrange for submission of 3 letters of

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through apply.interfolio.com/54771. Applications will be reviewed as they are

applications received by November 17, 2018.

Department of Neuroscience

New Haven, CT 06520-8001

http://medicine.yale.edu/neuroscience/index.aspx

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NRC Research Associateship ProgramsThe National Academy of Sciences, Engineering, and Medicine offers postdoctoral and senior research awards on behalf of 23 U.S. federal research agencies and affiliated institutions with facilities at over 100 locations throughout the U.S. and abroad. We are actively seeking highly qualified candidates including recent doctoral recipients and senior researchers. Applications are accepted during 4 annual review cycles (with deadlines of February 1, May 1, August 1, November 1).

Interested candidates should apply online http://sites.nationalacademies.org/PGA/RAP/PGA_046398

Awardees have the opportunity to:� conduct independent research in an area compatible with the interests of the sponsoring laboratory� devote full-time effort to research and publication� access the excellent and often unique facilities of the federal research enterprise� collaborate with leading scientists and engineers at the sponsoring laboratories

Benefits of an NRC Research Associateship award include:� 1 year award, renewable for up to 3 years� Stipend ranging from $45,000 to $80,000, higher for senior researchers� Health insurance, relocation benefits, and professional travel allowance

DESIRED SKILLS AND EXPERIENCEApplicants should hold, or anticipate receiving, an earned doctorate in science or engineering. Degrees from universities abroad should be equivalent in training and research experience to a degree from a U.S. institution. Some awards are open to foreign nationals as well as to U.S. citizens and permanent residents.

ABOUT THE EMPLOYERThe National Academies of Sciences, Engineering, and Medicine’s Fellowships Office has conducted the NRC Research Associateship Programs in cooperation with sponsoring federal laboratories and other research organizations approved for participation since 1954. Through national competitions, the Fellowships Office recommends and makes NRC Research Associateship awards to outstanding postdoctoral and senior scientists and engineers for tenure as guest researchers at participating laboratories. A limited number of opportunities are available for support of graduate students in select fields.

Position Title: Research Associate Professor

Req # 03919

Department of Chemistry at The University of Chicago invites applications for the position of Research Associate Professor. The successful candidate will be responsible for maintaining a research program and advise graduate students in Theoretical or Computational Chemistry. The candidate is expected to collaborate with experimental and/or theoretical faculty within the department. Ideally, candidates should have demonstrated ability to raise support for their research and lead collaborative projects.

teaching experience in Chemistry. The successful candidate will have demonstrated competence in teaching, and have experience mentoring graduate students in Chemistry. Candidates must have evidence of publication and research dissemination.

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Review of applications will begin November 15, 2018 and will

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[email protected] @newscientist newscientistLETTERS

Weighing the evidence on healthy fatness

From Jon Arch, Welwyn Garden City, Hertfordshire, UKClaire Wilson explains that as many as a third of people who are overweight have good scores for blood glucose, cholesterol and blood pressure (29 September, p 20). But why is this?

Many factors apart from body fat affect these scores. Another, underappreciated factor is that not all fat is equal.

The main component of stored fat, triglyceride, is not a problem (other than for weight-bearing joints) so long as it is tucked safely away in lipid droplets in small, subcutaneous fat cells. It is not the direct link between obesity and metabolic disease.

The problem comes when triglycerides are stored in large fat cells called adipocytes around the

gut in adipose tissue, or even worse in non-adipose tissues, notably skeletal muscle and liver. Here triglyceride produces metabolites that cause resistance to insulin, a feature of type 2 diabetes and other features of “metabolic syndrome”, such as high blood pressure and low-HDL (good) cholesterol.

This helps explain why the glitazone drugs, which shift fat from large visceral to small subcutaneous fat cells, can increase total body fat but improve insulin sensitivity.

Those rare individuals who are unable to make adipose tissue and direct their fat to muscle and liver are insulin resistant and often have symptoms of metabolic syndrome.

Exercise is more beneficial than you might expect from its effect on body fat content, because it burns off troublesome metabolites.

From Thelma Rowell,Ingleton, North Yorkshire, UKChelsea Whyte reports that in only seven species of mammal do females exhibit leadership (29 September, p 8).

Leadership is a difficult concept to apply to animals, and indeed different definitions seem to be applied in each of the seven species cited. I cannot

EDITOR’S PICK

offhand think of any species of large long-lived social mammal in which females don’t exert leadership in at least one of the definitions used here.

From my own observation, I can say that sheep and goats follow senior females’ decisions in foraging, as do African guenon monkeys, such as blue monkey females, which also defend territories. Males have other priorities, often spending time living in all-male bands with their own rules. Could the authors name seven mammal species in which males provide leadership?

The editor writes:■ The authors found leadership in 76 species, seven of which had systematic female leadership. Of course, females of the remaining species may take the lead at specific times and in specific situations.

For mammals, matriarchy is second nature

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“ I feel safer with the pilot having the same outcome as me!”

None of this means that losing fat has no benefit in an overweight individual. If other factors remain unchanged, it does.

Things we believe about economics and the world

From Nick Pattinson,Stockport, Greater Manchester, UKEconomics is “not an exact science, after all”, says Pascal Boyer (22 September, p 40). Economics is not a science at all. Where’s the largely agreed body of prior knowledge? Where are the experiments capable of falsifying?

Where – crucially – are the advances made by disproving previous theories? How come the same prescription produces different outcomes?

Unfortunately, the current discipline is the best we have, but please, let’s not forget its woeful

inadequacy, and let’s also not undermine science by applying the term where it doesn’t belong.

From John King,Humberston, Lincolnshire, UKPascal Boyer makes assertions that he is entitled to make in the field of psychology, but he makes claims in the field of economics that he is certainly not.

If you had asked a psychologist to write an article in which he discussed astronomy, and in that article he asserted that no planet has a retrograde motion, you would have been committing the same error.

The first of his “seven flawed ideas” – the notion that wealth is a fixed-size pie – certainly holds in sub-Saharan Africa.

His assertion that prices cannot be controlled by government regulation is wrong in the field of healthcare. All advanced countries

frequency; I understood that most Economy 7 meters switch tariffs as a result of a signal broadcast on BBC Radio 4 longwave.

I remember working with the UK National Grid in its London control centre in the 1980s. An important control it had was to compare, during the day, the time shown on a mains electric clock – “electric time” – with the time shown on an independent master clock, “clock time”.

A task of the control engineer was to adjust system frequency so that sometime around midnight, the clocks agreed. I assume that an equivalent system operates today.

Sword-makers were ahead of their time

From Malcolm Hunter,Leicester, UKI read your article about biological materials inspiring attempts to

have government controls on spending in healthcare, from Japan’s free market with price controls, to the UK with its relatively socialised medicine.

The only country that doesn’t attempt to control prices in healthcare is the US, where health costs are vastly higher than in any other advanced country and outcomes are relatively poor.

I am sure Boyer is correct in his psychological analysis, but he should be careful about his economic assertions.

Keeping time on the national grid

From David Clarke,Seaford, East Sussex, UKI am not sure why Steve Swift is having trouble with his electricity tariff timings ( Letters, 29 September). He says his meter takes its timing from the mains

@wotsapnin isn’t quite ready for the driverless aircraft of the

future (6 October, p 42).

>

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[email protected] @newscientist newscientistLETTERS

produce metals incorporating layers, or gradients in their composition or structure, in order to combine hardness and toughness (29 September, p 40).

Surely there is a long history of layering steel or iron to make weapons such as swords – with a hard, high-carbon edge, but a tougher, less brittle, lower-carbon core. Similarly, “case hardening” weapons and armour, using techniques to infuse steel surfaces with extra carbon, or with nitrogen to create surface nitride layers, also has a long history.

Are milk alternatives really the white stuff?

From Adam Croucher,London, UKThank you for Chelsea Whyte’s article on milk alternatives (22 September, p 22). It is high time that the question about the ecological and health impact of “alt-milks” is addressed in more detail – please write more!

The perceived benefits and harms of these “milks” have been left to marketing and the fashions of conscience. As a

consumer and fan of soy and oat milks (the latter comfortingly similar in flavour to Coffee- Mate), I still wonder often at the sense of consuming milk of any kind at all.

Alt-milks typically have complex and highly robust packaging that is neither compostable nor recyclable, and far bulkier than that used for milk, especially as alt-milks seem to come only in 1 litre packs.

Is it time for alt-milk producers to shorten their supply chains, package more renewably, and tell us more about what happens to all the bits of nut, bean, grain that don’t end up in their products?

Put Martian tourists on the no-fly list

From Edward Shields,Neebing, Ontario, CanadaAs a biologist and a space science enthusiast, I strongly object to Robert Zubrin’s push for immediate human exploration of Mars (8 September, p 22).

As humanity is witnessing on almost a daily basis, robotics and machine intelligence are opening

vast swathes of knowledge and new fields of space enquiry.

The huge amount of money spent on human space exploration has produced little cutting-edge science. One can only wonder what great science has been lost, or greatly delayed, due to funds channelled there instead of robotics and machine intelligence.

Those who count and those who are counted

From Andrew Shand,Irvine, Ayrshire, UKYou say that you surveyed a “representative sample of 2026 UK adults” to report on the public understanding of science and technology (22 September, p 6). But then you say “all interviews were conducted online”. So, did you just guess the views of those who are not?

The editor writes:■ Our survey was designed by Sapio, a market research company in London that employs accepted industry methodologies to obtain a nationally representative sample.

Letters should be sent to: Letters to the Editor, New Scientist, 25 Bedford Street, London, WC2E 9ES Email: [email protected]

Include your full postal address and telephone number, and a reference (issue, page number, title) to articles. We reserve the right to edit letters. New Scientist Ltd reserves the right to use any submissions sent to the letters column of New Scientist magazine, in any other format.

According to figures from the Office of National Statistics, 90 per cent of UK adults are “recent internet users” so any error margins associated with offline people not being online will be negligible.

Pouring cold water on green energy efforts

From Chris Hildred,Whitby, Ontario, CanadaEnid Smith reports that her self-sufficiency is thwarted because she can’t find a washing machine that doesn’t use a cold water fill, which is heated with expensive electricity (Letters, 8 September). She should try using cold water washing detergent — we’ve been using it for years!

The alien life hiding in plain sight

From Quentin Macilray,Limassol, Cyprus Cixin Liu postulates that highly civilised aliens would be as incomprehensible to us as we are to ants (8 September, p 42). Could this be the solution to Fermi’s paradox, “Where is everyone?” Answer: they’re already here.

For the record

■ The data artist with whom Hannah

Redler-Hawes co-curated the

[JOYCAT]LMAO exhibition is Julie

Freeman (29 September, p 44).

■ Estimates of the number killed by

Allied bombing raids on Germany in

1939-45 are in the hundreds of

thousands (6 October, p 16).



WHEN the 24 October 1968 edition of New Scientist was published, the space race was in full swing. The US had just completed a successful Apollo 7 mission, sending three astronauts into orbit for 11 days. We reported no details of the mission, however, concentrating instead on the 19th Congress of the International Astronautical Federation in New York. The success of the Apollo mission meant that the US was still aiming to have a man on the moon by the end of 1969, but the conference was apparently dominated by “the increasingly dim outlook for future space efforts”.

Budgets were being slashed as US taxpayers grew weary of funding adventures in space. It seemed that the once ambitious Apollo programme to explore large areas of the moon would be drastically cut back. And we learned that the Soviet Union was encountering problems with its programme, all but admitting that the Americans would beat them to the moon. Delegates were “gloomy”, we said, and the conference itself was “permeated by a general air of depression”.

Marginally more optimism came in reports of satellite developments. We predicted there might be as many as 130 satellites in orbit by 1980, and elsewhere that “there will be about $5 billion worth of spacecraft in orbit” by the same date. This latter figure would in turn justify the development of an “orbital scrap collector that could later be adapted for returning human cargo to Earth”.

In the meantime, a satellite repair vehicle currently under development would ensure that any damaged satellites could be fixed by remote control from Earth, although we added a note of caution for the superpowers. “It is easy to imagine the manipulators being used for sabotaging the other fellow’s spy satellite or diffusing his orbital bomb,” we warned.

Today we look back on the 1960s as being a golden era for space exploration. It would appear that hindsight can be unduly generous. Mick O’Hare ■

To delve more into the New Scientist archives, go to newscientist.com/article-type/old-scientist/

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AUTHORITIES in the US are giving

free helicopter rides to hundreds

of feral mountain goats, after the

animals developed an insatiable

thirst for human urine.

Olympic National Park in

Washington state is home to about

650 of the goats, which have started

to view hikers as wandering salt licks.

When not approaching park visitors to

lick their perspiration, the goats dig up

soil that ramblers have, er, seasoned,

damaging the trails in the process.

With few natural predators in the

park, and no approved contraceptive

medications, there is little to control

the goat population. Now rangers

plan to trap as many of the animals

as possible, transporting them by

helicopter to nearby forests that

offer a more suitable, presumably

salt-rich, habitat.

THIEVES in Germany have made off with an entire vineyard’s worth of grapes, estimated to be worth €8000. Police believe the criminals ran a professional harvesting machine over the entire vineyard, according to the

newspaper Die Rheinpfalz.It’s not the first large-scale

grape heist in the Rhineland-Palatinate region, famous for its Riesling, but the 1600-kilogram haul exceeds the 600 to 800 kilos of grapes stolen last year. Local vintners suspect that rivals are responsible, because of the specialised equipment required. “The motive is jealousy,” one winemaker told Die Welt newspaper. Might the culprits be suffering from sour grapes?

PSYCHOLOGISTS have dropped a

truth bomb on dog owners: your

pooch isn’t that smart. A team (cat

people, reckons Feedback) reviewed

more than 300 papers on animal

intelligence to compare dogs with

other carnivores, social hunters and

domestic animals, including cats,

dolphins and pigeons.

In many cases, they concluded

that experimenters had set out

to prove how clever dogs are, and

seen what they wanted to see.

And for each ability that was

claimed to be exceptional, they

found at least one other animal that

equalled dog performance.

“Taking all three groups into

account, dog cognition does not look

exceptional,” said Britta Osthaus of

Canterbury Christ Church University

in the UK. But surely this makes them

Jack Russells of all trades, if master of

none? Smart though dolphins may be,

Feedback has yet to see one fetch the

newspaper.

MANY will call it 2018’s most adorable trend: 3D-printed prosthetics for injured animals. In Canada, a dachshund with cancer got a new titanium skull after a brain tumour the size of an orange grew through her original one.

And south of the border, Mr Stubbs the alligator had his tail bitten off by other alligators at an illegal facility before he was rescued. The good medics of the Phoenix Herpetological Society in Arizona fitted him with a 3D-printed tail made from a material known as “dragon skin”. Meanwhile, students at Armorel High School in Arkansas created a 3D-printed foot for Peg the duck, whose foot had been chewed off by a peckish turtle.

Feedback could not substantiate reports that a pig in the UK was given a finely crafted wooden leg after pulling the farmer’s infant son from a pond, saving him from drowning. After such heroics, the Devon farmer reportedly said, “we couldn’t possibly eat him all at once”.

PREVIOUSLY, Feedback reported on

a Japanese rail company giving staff a

harrowing lesson in safety by forcing

them to sit in a trench by the track

as a train sped past (8 September).

Peter Jacobsen writes that in

Cariacica, Brazil, “a bus company

sought to sensitise its drivers to the

experience of cyclists by having their

drivers ride stationary bikes in the

road while buses passed them”.

London bus drivers, Feedback

thinks, will be only too familiar

with the experience of being

stuck stationary in the road.

A FARMER in Michigan has discovered that a rock he was using as a doorstop is a meteorite worth up to $100,000. When he bought another farm in 1988, the previous owner told him his father had seen the stone come down from the sky in the 1930s.

After keeping it for 30 years, he brought the 10-kilogram rock to Mona Sirbescu, a geologist at Central Michigan University. She determined that it was 88 per cent iron and 12 per cent nickel – an unusually high nickel content. “What I was holding is a piece of the early solar system that literally fell into our hands,” Sirbescu said.

The farmer, we presume, is investigating how many doorstops $100,000 could buy.

A SPATE of nuisance phone calls

emanating from the Ke Kai Ola seal

hospital in Honolulu, Hawaii, were

the work of an unlikely culprit.

Hospital director Claire Simeone

was one of many who received silent

calls from the centre, which she

eventually traced to a gecko perched

on a touchscreen telephone. Every

time it moved, this four-footed

telemarketer dialled numbers

stored in the recent calls log.

“I had to send out a note to all

of our staff and volunteers, who

may have received telemarketing

calls,” Simeone wrote on Twitter.

“I immediately hired [the] gecko.”

For more feedback, visit newscientist.com/feedbackFEEDBACK

You can send stories to Feedback by email at [email protected]. Please include your home address. This week’s and past Feedbacks can be seen on our website.

A man complaining of a headache discovered he had a 48mm nail embedded in his skull. The cement plant supervisor from Chongyang, China, told doctors he had no idea how it got there

PAU

L M

CDE

VIT

T


Last words past and present at newscientist.com/lastword

THE LAST WORD

Waxing miracle

Recipes often call for zest of unwaxed

lemons. Why are so many lemons

waxed, what kind of wax is used and

what is the best way to remove the

wax without harming the zest?

Citrus fruits have a robust natural waxy covering that protects them from drying out and from some kinds of rot. That kind of wax, in the amount found on fruit, presents no problems to the home cook.

The recipes that call for unwaxed lemons want to avoid the artificial wax used to coat some fruit. This is added for various reasons. For a start, industrial fruit production often depends on seasonal storage and international distribution of produce, which means it is at risk of deterioration, rotting and damage. Sometimes, fruit needs washing and other handling so vigorous that it damages the natural wax coating, spoiling the fruit’s appearance or permitting drying or rot. It might also be that the fruit just isn’t naturally glossy enough, so the handlers apply an extra coat to attract customers.

Sometimes the new coating is vegetable wax from other sources, and is much like the original wax, so it need not trouble the cook. But commonly it is a petroleum wax much like that used in candles, and applied in a thicker coat than the fruit naturally produces, to make it look extra glossy. Though harmless,

petroleum wax won’t break down in cooking and might affect some recipes, creating froths and making smooth items look unattractive. But if you are not fussy, any ill effects should be minor.Jon RichfieldSomerset West, South Africa

Bright spark?

Some restaurants celebrate

customers’ special occasions by

planting burning sparklers onto food,

showering it with sparks. Sparklers

typically contain an oxidising agent

such as potassium nitrate, which

yields nitrite as a combustion product.

The European Food Safety Authority

specifies a safety limit for nitrite

ingestion of 3.7 milligrams per day per

kilogram of body weight. How much

nitrite would someone ingest by

eating a slice of sparkler-enhanced

birthday cake?

Sparklers used on cakes will conform to a British European Standard, BS EN 15947 category F1, which means they will contain less than 7.5 grams of explosive.

In fact, sparklers used on cakes are likely to be somewhat smaller than this, containing, say, 3 grams of explosive. The black powder (sometimes called gunpowder) used as the explosive is typically

about 75 per cent potassium nitrate, which amounts to about 2.25 grams per sparkler. If it all decomposes to potassium nitrite, it would yield about 1.9 grams of this chemical.

This would be scattered all over the place, but let’s say 1 gram goes onto the surface of the cake. If the cake is then cut into 12 slices, that is 0.08 grams of potassium nitrite per slice, which is just over 1 milligram per kilogram of body weight for a 70 kilogram person.

So you could have three slices of sparkler-enhanced cake per day and stay within the European Food Safety Authority ingestion limit of 3.7 milligrams per day per kilogram of body weight. However, it’s not likely that this amount of potassium nitrite is produced.

It is also worth noting that potassium nitrite is a food additive, often labelled as E249. Peter Borrows Amersham, Buckinghamshire, UK

I think we are all safe from normal sparklers fired off one at a time on a cake, even if we don’t cut off the black bits in the icing.

However, there are not only sparklers, there are also mega-sparklers. These are very dangerous – and illegal in some countries. I have only seen them at Australian New Year celebrations, on a beach. As they say: Don’t try this at home.

They consist of perhaps 150 normal sparklers bundled together with wire. One central sparkler is left sticking up, used as

the ignition point. Combustion is almost instantaneous, a column of flame and smoke shoots up over a metre high and I suspect it forms a mushroom cloud, although it was too dark to tell.

Standing downwind with a glass of wine and a cupcake, as the mushroom cloud settles out, would surely mean that the wine and the cupcake would exceed a number of Australian and European food safety standards.Andrew CarruthersBeaconsfield, Quebec, Canada

The main nitrogen-containing chemical produced when using potassium nitrate in pyrotechnics is nitrogen gas, not potassium nitrite. I suspect the amount of nitrite produced is very small, if there is any at all. Eric KvaalenLes Essarts-le-Roi, France

This week’s question

SLEEPOVER

My husband is a lark and I am an owl when it comes to our attitudes to bedtime. This leads to discussions about the ideal time to go to bed. He is convinced that the best sleep happens before midnight, while I believe that no matter when you fall asleep, you are advised to get 8 hours and whether it starts before midnight or after has no relevance to the quality of your sleep. Who is right?Rita Szilagyi Szeged, Hungary

We pay £25 for every answer published in New Scientist. To answer a question or ask a new one please email [email protected]. Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.

You can also send questions and

answers to The Last Word, New Scientist, 25 Bedford Street, London, WC2E 9ES.

New Scientist Ltd retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format and at any time in the future. All unanswered questions and previous questions and answers are at newscientist.com/lastword/

“ You could have three slices of sparkler-enhanced cake a day and stay within the safety limit for nitrite”


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