Considerable controversy has taken place between those who favor quota sampling and those who advocate area sampling in opinion polling. This article does not attempt to give a final solution to the ...

Accurate atomic models of macromolecular structures are invaluable for understanding the biochemical and cellular processes carried out by proteins. Recent advances in cryo-EM 1,2 have led to a ...

Air and surface sampling techniques currently used by the US government are effective in fighting bioterrorism and potentially saving lives, a former Department of Homeland Security medical officer ...

This is a preview. Log in through your library . Abstract Maintaining native plant diversity, detecting exotic species, and monitoring rare species are becoming important objectives in rangeland ...