Some scientists now believe that tension headaches may result from changes among brain chemicals such as serotonin.

VOA: special.2010.03.30

Some researchers and editors say changes must be made to stop such false author claims.

VOA: special.2009.10.08

They say such changes are events that have always happened.

VOA: special.2010.01.19

But in the end, protests and peaceful revolutions, such as in Poland,and changes in Moscow brought it down.

VOA: standard.2009.11.09

But Blatter and many in the football governing hierarchy have opposed such changes, saying they halt the free-flowing movement of the game and do not eliminate all mistakes.

VOA: standard.2010.06.29

A Royal Society research team member, Jules Pretty, says the team took into account a number of changes that are expected in coming decades, such as climate change, massive rises in world population, and new consumption patterns.

VOA: standard.2009.10.21