21.   Koolhaas delights in the ability of cities to triumph over the common sense of urban planners, to defeat their prosaic ideas for low density and open space.

22.   Recent snow that has fallen on the upper slopes had relatively low density because of the chilly conditions that prevailed.

23.   The bad news, though, is that the solution to the age crisis seems to require that the universe has a low mass density.

24.   The relatively low density of hot air reduces aerodynamic lift.

25.   These cells release fatty acids directly into the liver, where they are converted into very low density lipoproteins.

26.   This appeared to confirm earlier intimations of a universe with a mass density too low to fit many theories.

27.   West African crudes such as Bonny Light are favored by refiners because their low density and low sulfur content make them well suited for gasoline production.

28.   Zoning policies bar mixed-use development and enforce low density housing.

29.   This low density tells us something about the composition of the planet.

30.   Up to now, scientists had been focusing on LDL, or low density lipoprotein, as a main factor in coronary risk.