The Economist - UK (2022-05-07)

The Economist May 7th 2022 Science & technology 75

field’s  IntegratedVehicleHealthManage­
ment  Centre,  proposesinsteada “reason­
ing  system”  thattakesanoverviewofthe
individual monitoringsystems.
Because it isnotpracticaltoputa sen­
sor onto every potentiallybreakablepartof
an  aeroplane,  lestitenduptooheavyto
take  off,  this  willuseaitrained to find
faults which canbedetectedfrombroader
measurements,suchaspatternsofvibra­
tion  and  temperaturechanges.Moreover,
such a whole­planedigitaltwinislikelyto
reside in the aircraftitself,ratherthanrely­
ing  on  vast  amountsofraw data being
transmitted to amaintenancebaseforpro­
cessing. That willprovideswifteranalysis
and avoid transmissionbottlenecks.
All this willenableanaircrafttorecon­
figure  such  thingsasbatteryconnections
and fuel use onthefly,asitwere.Therea­
soning  systemwouldalsokeepaneyeon
things like the weathertheaircraftwasop­
erating  in,  becausethese,too,caneffect
the  wear  and  tearofparts.Flyingthrough
dust  clouds,  forinstance,can accelerate
the abrasion ofengineparts.
The  aircraftwouldcommunicatewith
its  pilots  (assumingthere wereany, for
some future aircraft,especiallyfreighters,
may well be drones)andalsowithground
engineers.  Suchaplanewould,insome
sense,  be  “aware”ofhowitsvariouscom­
ponents  were  performingandinteracting
with  one  another.Itisthislevelofself­
awareness whichtheresearchersuseasan
excuse  for  describingthesystemascon­
scious, a term whichtheysayreflectsa di­
rection of travelratherthana goal.
That self­awarenesswould,though,al­
low the plane tobookitselfinformainte­
nance when needed,ratherthanona fixed
schedule,  and  toorderanysparepartsre­
quired in advance.Thepredictivemainte­
nance such a systemwouldprovideshould
help avoid unscheduledstopoversandre­
pairs.  Every  daywhicha passengerjetre­
mains on the groundcostsseveralhundred
thousand  dollarsoflostrevenue.DrJen­
nions  reckonsaconsciousaircraftcould
cut maintenanceexpensesbyaround30%.
Such  maintenancemightalsobeauto­
mated, at least inpart.Cranfield,whichbe­
gan  as  an  aeronauticscollegein1946,has
its own airport,a hangaranda Boeing 737
to  experimenton.Theresearchersareex­
ploring  the  useofdronesequippedwith
optical  and  thermalsensorstoflyaround
an aircraft in a hangar,lookingforexternal
anomalies. Meanwhile,tinysnakelikeser­
vice robots couldcrawlintoenclosedareas
such as fuel tankstoconductrepairs.
The  Cranfield team hope to have a
whole­aircraft digital twin operating by
2024 and a prototypewitha degreeofself­
awareness  flyingonanaircraftby2035.
Whether  such a system will include a
sense of shameforlousycabinservicere­
mains to be seen.n

Sheepfarming

Turning the worms

S

heep farmersin AustraliaandNew

Zealandhavea problem.Theircharges

are susceptible to intestinal nematode

wormswhichcausethemtowasteaway

andcan,inseverecases,killthem.

Overtheyears,thewormshaveevolved

resistance to drugs once usedto attack

them.Butasecondapproachistobreed

countermeasures into the sheep them­

selves.Thiscanbedonebycountingthe

number ofwormeggsinanimals’drop­

pings and selecting as sires and dams

thosethathavethefewest,ontheassump­

tionthatthesearethesheepwiththeleast

worm­friendlyguts,andthatthisproperty

willshowupintheiroffspringaswell.That

works.Buthow,hasbeenobscure.A study

justpublishedinAnimalMicrobiome, byEr­

winPazoftheUniversityofWesternAus­

traliaandhiscolleagues,throwslighton

thematter.Itsuggeststhatwhatisbeing

bredforisa propensitytodevelopa worm­

hostilegutmicrobiome.

Gut microbial health, once a fringe

medical interest,isnowmainstreamfor

humanbeings,asbugsinthealimentary

canalarelinkedwithconditionsranging

fromobesitytoarthritis.Butwhatistrueof

peopleistrueofotheranimals,too.And,in

thecaseofsheep,DrPazandhiscollabora­

torsseemtohavehitthejackpot.

DrPazknewfrompastworkthatsheep

withsevereworminfestationstendtohave

abnormal  bacterial  populations  in  their

faeces. This led him to wonder whether the

bugs  in  the  guts  of  resistant  sheep  were

somehow  hampering  the  worms’  activi­

ties. He and his team therefore looked at a

flock  of  200  sheep  at  a  farm  in  Western

Australia and selected ten that had particu­

larly high loads of worm eggs in their fae­

ces  (1,940  per  gram,  on  average)  and  ten

that  had  low  loads  (410  per  gram).  These

unfortunate  sacrificial  beasts  were  then

slaughtered and their entrails examined—

not for auguries of the future but for their

microbial populations.

As  they  had  hoped  to,  the  researchers

did indeed find systematic differences be­

tween the microbiomes of the two groups.

These  differences  were  particularly  nota­

ble in the small intestine, where the worms

live, with resistant sheep having richer and

more diverse bacterial populations in this

part of the gut than vulnerable animals did.

In particular, the team noticed that popula­

tions  of  bacteria  which  ferment  carbohy­

drates such as cellulose and turn them into

short­chain  fatty  acids  were  especially

abundant in the resistant animals.

It is, of course, possible, that the worms

are  affecting  the  sheep’s  microbiomes,

rather  than  the  other  way  around.  But  Dr

Paz  thinks  this  is  unlikely,  because  all  of

the  sheep  looked  at  had  at  least  some

worms. Rather, he suspects, genetically re­

sistant  sheep  are  providing  an  intestinal

environment conducive to bacteria which

either  produce  compounds  that  repel  the

worms  or  consume  resources  which  the

worms  depend  upon.  If  that  is  correct,  it

opens  up  a  third  approach  to  worm  con­

trol, which is to employ probiotics to shape

the  gut  microbiomes of  flocks  directly,

rather than relyingonselective breeding to

do it at one remove.n

Gut bacteria may help fight nematode

infestations in sheep

Safely grazing