The Economist May 7th 2022 Science & technology 75
field’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 find
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
figure such thingsasbatteryconnections
and fuel use onthefly,asitwere.Therea
soning systemwouldalsokeepaneyeon
things like the weathertheaircraftwasop
erating in, becausethese,too,caneffect
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 whichtheysayreflectsa di
rection of travelratherthana goal.
That selfawarenesswould,though,al
low the plane tobookitselfinformainte
nance when needed,ratherthanona fixed
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.Cranfield,whichbe
gan as an aeronauticscollegein1946,has
its own airport,a hangaranda Boeing 737
to experimenton.Theresearchersareex
ploring the useofdronesequippedwith
optical and thermalsensorstoflyaround
an aircraft in a hangar,lookingforexternal
anomalies. Meanwhile,tinysnakelikeser
vice robots couldcrawlintoenclosedareas
such as fuel tankstoconductrepairs.
The Cranfield team hope to have a
wholeaircraft digital twin operating by
2024 and a prototypewitha degreeofself
awareness flyingonanaircraftby2035.
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
willshowupintheiroffspringaswell.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
flock 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 sacrificial 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 find systematic differences be
tween the microbiomes of the two groups.
These differences 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 affecting 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 flocks directly,
rather than relyingonselective breeding to
do it at one remove.n
Gut bacteria may help fight nematode
infestations in sheep
Safely grazing