The EconomistMay 16th 2020 Science & technology 712
1found on the surface membranes of certain
cells—particularly those of the airways
into the lungs. The ape version of ace2 is,
Dr Melin has discovered, identical to the
human variety, so apes are likely to be par-
ticularly susceptible to sars-cov-2.
Conservationists are worried. “What’s
nerve-racking about covid-19 is its novel-
ty,” notes Richard Wrangham, a chimpan-
zee expert at Harvard University. But pri-
matologists like Dr Wrangham are already
familiar with the harm caused by diseases
of human origin. Though conservation ef-
forts have protected many apes from habi-
tat loss and poaching, the Faustian bargain
made to do this, says Peter Walsh, an ape
conservationist at Cambridge University,
is that the apes are then exposed to poten-
tially deadly viruses.
Dr Walsh and a group of colleagues at
Thomas Jefferson University, in Philadel-
phia, and at the University of Louisiana, La-
fayette, estimate that Ebola alone is re-
sponsible for the deaths of a third of the
world’s wild gorillas over the past three de-
cades. Human respiratory viruses are the
leading cause of death among chimpan-
zees at Gombe Stream National Park in Tan-
zania and Kibale National Park in Uganda.
Tony Goldberg of the University of Wiscon-
sin-Madison was “intellectually prepared,
but not emotionally prepared” for the dev-
astation caused in 2013 by an outbreak of
rhinovirus cat Kibale, which killed 9% of
one group of chimps. A covid-19 outbreak
would be “another problem that the apes
don’t need”, he observes.
Jane Goodall, a pioneering primatolo-
gist who began her research on chimpan-
zees at Gombe 60 years ago, is also worried.
Tanzania has not enforced a full anti-covid
lockdown, so villagers who live around the
park could still spread the disease to the
chimps. At Tchimpounga Chimpanzee Re-
habilitation Centre in Congo-Brazzaville,
where her research institute also works,
health checks are mandatory for humans
and chimps alike.
The closure of conservation sites be-
cause of the pandemic poses another pro-
blem for apes. Around 40% of Virunga Na-
tional Park’s revenue has disappeared
overnight, says Emmanuel de Merode, its
director. “This will present major chal-
lenges to ensuring that conservation ef-
forts continue uninterrupted,” he adds. Dr
Walsh fears that if local economies are
harmed by the closure of tourism sites,
people will turn to poaching.
Some ape populations will cope with
covid-19 better than others. Though chim-
panzee troops are generally controlled by a
dominant adult male, there are usually
plenty of subordinates willing and eager to
step in, should he die or be incapacitated.
Mountain-gorilla groups, however, are
normally harems that have several females
but only a single adult male. If this silver-backweretodieofcovid-19,thefemales—
likelytohavebeeninfectedaswell—would
probably disperse to join other groups,
spreadingthevirusfurther.
MrdeMerodesaysthatif a gorillatested
positiveforcovid-19,hispark“wouldcon-
sideraveterinaryinterventiontoisolate
andtreattheindividual,butwewouldbein
unknownterritory”. Mostprimatologists
thinkisolatinga sickapewouldbeunfeasi-
ble.Rather, lamentsDr Wrangham, “we
wouldjusthavetositbackandwatch.” 7T
hey may befacing extinction in the
electric-transport revolution, but one
benefit of cars with internal combustion
engines is that they are easy and quick to
refuel, so travelling a long way in one is
rarely a problem. Not so for their succes-
sors. In the absence of universal standards,
electric cars come with a variety of charg-
ing systems and different sorts of cables
and sockets. Extended journeys therefore
need careful planning to make sure that the
battery is fully charged at the start and that
compatible fast-charging stations are
available en route.
It would be much more convenient if
electric cars could be recharged wirelessly.
Some electric toothbrushes and other
small devices, such as mobile phones, can
already be topped up in this way using a
process called electromagnetic induction.
This employs an alternating mains current
flowing through a coil to create a varyingmagnetic field, which then generates an-
other current in a second coil placed along-
side it according to principles elucidated in
the 19th century by Michael Faraday. The
device containing the second coil then
converts the transmitted power into direct
current, which is used to recharge a battery.
As users of electric toothbrushes and
phones will know, device and charger must
be both close to each other and precisely
aligned for this process to work. That is
tricky to achieve with an electric car, which
sits above the ground and requires higher
levels of energy transfer.
These problems are being overcome
with advances like that made by WiTricity,
a firm based near Boston, Massachusetts.
This company was founded in 2007 to com-
mercialise the work of Marin Soljaèiæ and
his colleagues at the Massachusetts Insti-
tute of Technology. Dr Soljaèiæ knew, in
theory, that by having the transmitting and
receiving coils resonate at the same fre-
quency it should be possible to transfer
greater amounts of energy over longer dis-
tances, and he sought to turn that knowl-
edge to practical account. In one experi-
ment, he and his colleagues sent enough
power over a two-metre gap to illuminate a
60 watt bulb. They also did safety tests and
found that transmission of this power
could be done without harming people in
the vicinity.
WiTricity is working with a number of
carmakers and sold its first commercial
system in 2018 to bmw, which fits it to some
of its 530e hybrid cars. Alex Gruzen, WiTric-
ity’s boss, expects further developments
soon. He says the arrangement can trans-
mit power from the grid to the car’s battery
with an efficiency of up to 93%, which is
similar to that achieved by a plug-in sys-
tem. Nor does a car’s receiving coil have to
be positioned directly above the charging
pad on the ground—a useful feature of res-
onating coils being that they do not have to
be so closely aligned to transmit power.
As to how much power can be trans-
ferred, and how quickly, this is a question
of cost and design. For most uses at home, a
wireless charger of 11 kilowatts might suf-
fice. That would provide around 50km of
range per hour of charging and cost around
$2,000, says Mr Gruzen. At this price, he
says, a wireless system would be competi-
tive with plug-in home-charging units.
Another advantage of wireless recharg-
ing is what Mr Gruzen calls “power snack-
ing”. This is topping up the battery when a
car is stationary for a short time. The com-
pany provides systems to recharge taxis in
this way while they wait in line, and to do
the same for electric buses at bus stops. It is
also possible to charge vehicles while they
are on the move. That might make sense in
places where vehicles often queue up, such
as at airports, but Mr Gruzen does not think
digging up motorways to install a chargingWireless vehicle-charging is starting to
look promisingWirelessly charging electric carsIt’s time to cut
the cord