2019-10-19_New_Scientist

19 October 2019 | New Scientist | 19

Ancient humans

Animal cognition Cancer

Corals on the brink

of death can recover

Marine heatwaves degrade

reef-building corals, but a

16-year study of Cladocora

caespitosa has shown that

this endangered coral’s

polyps may only look dead

(Science Advances, doi.org/

dchd). They shrink and

retreat into a hard skeleton,

but can regrow over time,

a survival strategy that is

seen in ancient corals.

Ancient DNA reveals

Bronze Age slaves

Slavery may have started

in the Bronze Age, about

1300 years earlier than

we thought. Analysis

of ancient DNA from

104 individuals found

generations of rich families

adorned with jewellery or

weapons buried with poor,

unrelated people who may

have been live-in slaves

(Science, doi.org/gf9rmr)

Twisted fridges

could save energy

Nickel titanium wires cool

when they are twisted and

then released. A model

fridge based on this idea

cooled water as it passed

over the untwisting wire

(Science, doi.org/dcmj).

If scaled up, this approach

could provide refrigeration

that is more energy

efficient than traditional

compressed gas systems.

Cave people used

bones as a food store

OUR distant ancestors had the

foresight to put aside bones from

animals so they could eat the

fatty marrow later. This is the first

evidence that ancient humans

delayed eating food and indicates

they could plan ahead.

Ran Barkai at Tel Aviv University

in Israel and his team analysed

more than 80,000 animal bone

specimens from Qesem cave in

Israel to determine precisely

how ancient humans accessed

HONEYBEES may be better at

counting when penalised for errors

compared with when simply

rewarded for correct answers.

We already had some evidence

suggesting bees can count to four.

But it turns out they may be capable

of understanding larger numbers.

To investigate, Scarlett Howard at

the University of Toulouse in France

and her team trained bees to enter a

chamber from where they could see

two channels with images, one with

an image of four shapes and the

other showing one to 10 shapes.

The bees were then split into two

groups. The first were trained to

pick the image with four shapes,

getting sweet sucrose for choosing

that and bitter tasting quinine for

the other image. The second group

got sucrose for the four-shape

image, but weren’t penalised for

choosing the other image. The team

then tested whether the bees could

identify images of four shapes

compared with five, six, seven or

eight shapes.

Only bees conditioned with both

reward and penalty could pick the

four-shape image at a level higher

than would be expected by chance.

This also suggests they can grasp

numbers beyond four (Journal of

Experimental Biology, doi.org/dcj2).

Jason Arunn Murugesu

the bone marrow. Humans lived

in this area about 200,000 to

400,000 years ago.

The team noted characteristic

cut marks on 78 per cent of the

bone surfaces, consistent with

bone preservation and delayed

consumption. These result from

the effort required to remove

dried skin from preserved bones.

The researchers also tested how

bone marrow degrades over time.

They exposed 79 bones from red

deer to outdoor conditions, as well

as a simulated indoor cave setting.

Then they experimented with

removing the skin and flesh from

Tumour in a dish can

test chemo benefits

TINY organoids grown from a

person’s cancer cells could help

predict if chemotherapy will work.

At the moment, it is difficult to

know whether a chemotherapy

will help an individual. Although

the drugs are often lifesaving, for

some they can trigger bad side

effects without having any benefit.

To better predict if a treatment

will work, teams are turning to

personalised organoids grown

from clumps of cells biopsied from

a person’s tumour. The idea is that

the organoid serves as a lab model

for that person, and the drugs that

kill cells in the lab are more likely

to work on their tumour.

Emile Voest at the Netherlands

Cancer Institute and his colleagues

tested this idea using 35 organoids

grown from tumour cells from

people with colorectal cancer. They

gave some organoids a drug called

irinotecan and found it seemed to

work similarly in the organoids

and the individuals. Organoid use

correctly predicted how eight out

of 10 people responded to the drug.

But the organoids failed to show

if a combination of irinotecan and

a drug called oxaliplatin would

work. This may be because they

are too simplistic a model (Science

Translational Medicine, doi.org/

gf9p32). Jessica Hamzelou

the bones at various times during

nine weeks of storage. The number

of short incisions and marks left

increased when this removal was

done after four or more weeks,

leaving a similar pattern to those

seen on the bones from the cave.

The team found that the skin-

covered bones could withstand

nine weeks of exposure during

autumn without losing a

significant amount of nutritional

value, but the fat within them

degraded after the third week in

spring and in indoor conditions

(Science Advances, doi.org/dchf).

Layal Liverpool

To bee the best with numbers

try a stick and carrot method

GEORGETTE DOUWMA/SCIENCE PHOTO LIBRARY

PROXYMINDER/GETTY IMAGES

Really brief

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