But in a recent study they declared that forty percent of the tweets captured over a two-week period were "pointless babble."

VOA: special.2009.09.14

But this home contains over 2,000 pieces of art organized from room to room by period and by geography.

VOA: special.2009.01.11

Medical experts say small amounts of carbon monoxide over a long period of time can greatly harm an unborn baby.

VOA: special.2010.02.02

A recent study showed that RTS,S reduced clinical cases of malaria by fifty-three percent over an eight month follow-up period.

VOA: special.2010.04.20

"American exports grew almost seventeen percent over the first four months of this year, compared to the same period last year.

VOA: special.2010.07.09

Researchers in the United States say drinking a lot of alcohol over a short period may influence genes involved in bone formation.

VOA: special.2010.08.31

They used information gathered over a period of 20 years, until 2003, in the Framingham Heart Study.

VOA: special.2009.01.21

The researchers studied the diets of thirty-one thousand children ages two to eighteen over a thirty-year period.

VOA: special.2010.03.17

They found that over a period of six years, planting three rows of trees reduced total dust and ammonia by more than half.

VOA: special.2009.09.08

The rock formations there are the result of deposits made by ancient lakes and rivers over a period of about twenty million years.

VOA: special.2009.04.15

The unusually long period of cold weather has shown how even warm climates can sometimes freeze over.

VOA: special.2010.01.12

Volunteers received vaccinations over a period of six months and were tested for H.I.V.

VOA: special.2009.09.30

"The Lost Symbol" takes place in Washington,D.C., over a period of just twelve hours.

VOA: special.2009.10.09

Doctors use it to control moderate to severe pain over a long period.

VOA: special.2009.02.10