Bart Sullivan, a senior vice president at WSP Cantor Seinuk, a firm that handles engineering for buildings like One World Trade Center, says building a residential skyscraper is generally more challenging than building a tall office building, partly because residential buildings have fewer internal columns and other core structural elements.

WSJ: Living The High Life

Embedding the structural support in the core made it possible to cantilever the roof and thus wrap a glass facade around the building, using vast expanses of insulated, triple-pane glass and mahogany mullions.

WSJ: The Greening of a Midcentury Classic

The core economies have deep structural problems and the world economy is in a state of disequilibrium, says Jan Dehn, an economist at Ashmore Group in the U.K. Ashmore has its hands in emerging market debt.

FORBES: The M��nage ? Trois Keeping This Market Alive

Recruiting and developing a core of well-rounded IT professionals is laden with structural obstacles and unrealistic expectations.

FORBES: Here's the CIO Playbook for the Next 5 years

There is a structural change in the global economy, with slower growth in the core economies and troubled governments, and stronger growth in the emerging economies with stable governments.

FORBES: Economies Of Brazil & UK Show How Poor Get Rich Slowly

The Chinese leadership that emerges from 2012 will likely be unwilling or unable to decisively carry out deep structural reforms, obsessively focused on maintaining internal stability, and more aggressive in pursuing the core strategic interests it sees as essential to this stability.

FORBES: Overhaul Coming To China's Leadership