GREENLAND

Geologists discovered what some think may be the oldest known fossils on earth. The scientists said the objects are 3.7-billion-year-old stromatolites, layered structures created by lime-secreting cyanobacteria.

U.K.

The British government imposed a tax on companies that sell products with added sugar. Proponents hope the levy will help reduce obesity among children.

SYRIA

An analysis of mortality data from 22 countries in the Middle East and northern Africa found that conflict and civil strife have decreased life expectancy across the region. In Syria, for example, the life expectancies of both women and men are now about five years lower than in 2010.

AUSTRALIA

Over the past two decades a contagious cancer, called devil facial tumor disease, has reduced the population of Tasmanian devils by more than 80 percent. But new research shows that the animals may be developing resistance to the disease.

SOUTH AFRICA

The first large-scale clinical trial since 2009 of a vaccine against HIV begins this month. The three-year program will include 5,400 people across four sites. Nearly two thirds of the 2.1 million new HIV infections reported worldwide in 2015 were in sub-Saharan Africa. 

U.S.

The Centers for Disease Control and Prevention announced that the nasal spray form of the flu vaccine does not work. Preliminary research indicated that during the last flu season, the spray was only 3 percent effective in children between the ages of two and 17. The agency now recommends the flu shot for everyone.