It's more like simple invisibility, because of increasing geographic, occupational and social barriers that block one group from the other's view.

"Patients don't know other individuals who have similar burdens, and there are also geographic barriers to Parkinson's specialists," he says.

But new geographic, occupational and social barriers are blocking them from the sight of the rich.

In that long, lean country, impressive geographic barriers limit the distribution of species.

Because of the really formidable geographic and cultural barriers.

These geographic barriers kept the interior of Oman free from foreign military encroachments.

The last major geographic barrier to entering Atlanta had been overcome.

Seeing firsthand how the Internet could break down economic and geographic barriers, she began thinking about going into business for herself.

While the racial lines in the sport are slowly beginning to fade, the geographic barriers have all but fallen.

The river stood as a major geographic barrier dividing northern and southern China.