Science - USA (2022-04-29)

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PHOTOS:
TOP TO BOTTOM REIDAR HAHN/FERMILAB; Å GE HOJEM/NTNU UNIVERSITY MUSEUM

Vikings sold ivory in Ukraine

ARCHAEOLOGY |Vikings shipped walrus

ivory from Greenland far away to Kyiv,

according to new analyses of ancient walrus

skulls and ivory figurines discovered in the

Ukrainian capital. The 4000-kilometer trade

route is much longer than was thought

based on previous studies, which suggested

eastern users of the coveted material

sourced it only from walruses caught in

the Russian arctic. After discovering fin-

ished ivory artifacts and discarded walrus

skull fragments in a Kyiv layer dating to

the 1100s C.E., an international

team used DNA and chemical

analyses to link the material

to a genetic group of walruses

found only in the western

Atlantic Ocean. Vikings

appear to have overhunted

the Greenlandic walruses,

and the authors say con-

sumer demand in Eastern

Europe may have been

responsible. A decline in harvest could also

help explain why Norse settlers abandoned

Greenland in the 1300s.

Asteroid explorer gets 2nd target

PLANETARY SCIENCE |Next year, after

swinging past Earth and dropping off a

cargo of rocks it collected from the asteroid

Bennu, NASA’s OSIRIS-REx spacecraft will

embark on a new mission to the asteroid

Apophis, the agency said this week. In 2029,

the 300-meter-wide Apophis will zip past

Earth in the closest flyby of a large asteroid

in modern records; at one-tenth the distance

to the Moon, it will be visible to the naked

eye. Afterward, the renamed OSIRIS-Apex

mission will visit and collect data from the

asteroid for 18 months. Although the space-

craft cannot collect any more rocks, it will

gauge how Apophis’s orbit was perturbed

by Earth’s gravity and conduct an approach

maneuver to scorch off the asteroid’s surface

layer, exposing hidden layers below.

Most in U.S. show signs of infection

COVID19 |Nearly three in five U.S. resi-

dents had been infected with SARS-CoV-

Walrus ivory, used in this carved

specimen from Norway, was widely

prized in early medieval Europe.

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F

ermi National Accelerator Laboratory (Fermilab) last week

won final approval to build a new superconducting linear

accelerator that will generate an intense beam of protons

with an energy of 800 million electron volts. Researchers will

use that beam to create elusive particles called neutrinos and

shoot them 1300 kilometers through Earth at a planned under-

ground detector in South Dakota for high-priority experiments.

The new accelerator, the Proton Improvement Plan-II, replaces

an older one with half the energy. Workers had already begun to

construct buildings for the new machine; last week’s go-ahead

from the U.S. Department of Energy lets the lab build the actual

accelerator. All told, the project will cost $978 million, not includ-

ing equipment contributions from other countries totaling roughly

$330 million. Completion is expected in 2032.

PARTICLE PHYSICS

Fermilab neutrino source gets green light for construction

A new U.S. accelerator will speed up particles using a series of these five-cell, superconducting, radio-frequency cavities.

by February, a sign of the speed with which

the highly contagious Omicron variant

surged, the Centers for Disease Control and

Prevention reported this week. Starting in

September 2021, researchers analyzed tens

of thousands of blood samples collected

each month, measuring antibodies that

are generated by exposure to the virus but

not by the vaccines available in the United

States. From December 2021 to February,

as Omicron took off, the portion of samples

with the antibodies rose from 34% to 58%

across all age groups. In children and ado-

lescents, the least vaccinated age groups,

the proportion rose from 45% to 75%, the

researchers reported on 26 April in the

Morbidity and Mortality Weekly Report.

Other studies have shown that COVID-

vaccines protect most recipients against

severe illness, but effectiveness against

infection, especially by Omicron, wanes.

Avoidable COVID-19 deaths tallied

PUBLIC HEALTH |About 234,000 U.S.

deaths from COVID-19 since June 2021 could

have been prevented if all eligible adults had

received the primary series of vaccinations,

an analysis by the Kaiser Family Foundation

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