New Scientist - International (2019-11-23)

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23 November 2019 | New Scientist | 19

Genetics

Diet Solar system

Hayabusa 2 says
sayonara to Ryugu

Japan’s Hayabusa 2
spacecraft has begun its
return journey to Earth
from the asteroid Ryugu,
carrying two samples of
the space rock back for
analysis. “This is an
emotional moment,” the
team (above) posted on the
mission’s Twitter account.

Big emissions from
US video gaming
A study of the energy use of
gaming in the US has found
that it produces annual
emissions on a par with
Sri Lanka’s: 24 megatonnes
of carbon dioxide. Better
graphics, a move to 4K
monitors and TVs and
the growth in streaming
games are all energy
hungry developments
(The Computer Games
Journal, doi.org/dd7m)

Fish can judge how
far they have gone

Triggerfish have an
impressive ability to
estimate the distance they
have swum, and scientists
think that understanding
this may shed light on
how all animals with a
backbone evolved the
ability to navigate spaces.
Researchers trained the
fish to swim a set distance
in order to acquire food
(bioRxiv, doi.org/dd7n).

Bygone era’s family
secrets revealed

POORER 19th century families
in Europe’s cities were more
likely to include children who
weren’t biologically related to
their legal fathers, according
to a genetic study.
It is widely assumed many men
aren’t the biological fathers of
their children. So-called extra-pair
paternity has been claimed to be
as high as 30 per cent today. But
over the past two decades, DNA
studies have shown the average

DITCHING carbohydrates and
eating lots of fat may give some
protection against flu. Feeding mice
the so-called keto diet seems to
boost certain immune cells, which
may be responsible for the effect.
The keto diet forces the body to
burn fat for energy, which can help
with weight loss, and people may
get flu-like symptoms known as
the “keto flu” as they adapt to
eating fewer carbs.
Akiko Iwasaki at Yale School
of Medicine and her colleagues
previously found that the keto diet
reduced inflammation in mice with
gout. Because inflammation is
common to both gout and flu, they

thought the diet may also help with
flu-related inflammation, which
can severely damage the lungs.
To test this, the team fed mice
infected with influenza A – the most
serious type of flu – either a keto or
standard diet for a week before
infection. After four days, all seven
mice fed a standard diet succumbed
to the flu, compared with only five
out of the 10 mice on the keto diet.
The keto diet mice also didn’t lose
as much weight, which is usually a
clear sign of flu infection in animals.
These mice had more of a type of
T cell found in the lungs that is key
to an immune response (Science
Immunology, doi.org/dfbd). GL

rate is actually around 1 per cent.
Maarten Larmuseau at KU
Leuven in Belgium wondered if
social class might have made a
difference to this in past centuries.
His team identified 500 pairs
of men in Belgium and the
Netherlands where, according
to genealogical records, each
pair descended from the same
male ancestor through a male
lineage. Half of these ancestors
were born before 1840 and the
oldest was from 1315.
DNA testing allowed the team to
work out that the rate of extra-pair
paternity among farmers and

Titan’s surface
features mapped

SLOWLY but surely, the face of
Saturn’s strange moon Titan is
being revealed. Researchers have
made the first map of the geology
of its entire surface.
Titan’s atmosphere is full of
a thick, orange haze that blocks
light, making it difficult for
spacecraft to take pictures. NASA’s
Cassini probe, which orbited
Saturn from 2004 to 2017, took
radar and infrared data of Titan’s
surface, giving a hint of the terrain.
Now, Rosaly Lopes at NASA’s Jet
Propulsion Lab in California and
her colleagues have analysed that
data to map lakes, craters, dunes,
plains, hilly terrain and heavily
eroded, labyrinthine plateaus.
They found the landscape type
depended strongly on the latitude.
The equator is mostly covered in
dunes, with flatter plains in the
mid-latitudes and lakes and
labyrinths closer to the poles.
They were able to determine that
the oldest areas on the surface are
probably mountains, which are
bits of the moon’s icy crust.
The youngest areas are the lakes
and dunes. Sand from the dunes
seems to be blowing over the
plains, creating a fuzzy border
between the two zones (Nature
Astronomy, DOI: 10.1038/s41550-
019-0917-6). Leah Crane

more well-to-do craftsmen and
merchants was about 1 per cent,
rising to 4 per cent among
labourers and weavers and
nearing 6 per cent among
working class people in densely
populated cities in the 19th
century. The overall rate was still
low, at 1.6 per cent per generation
(Current Biology, doi.org/dd78).
What the study can’t reveal is
why some were more likely to be
in this situation. One possibility is
that poorer women in such cities
were more vulnerable to male
sexual violence and exploitation.
Michael Le Page

High-fat, low-carb regime


helps mice avoid the flu


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