New Scientist - International (2019-11-23)

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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Really brief

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