The transition from an ice age to an ice-free planet 300 million years ago was highly unstable, marked by dips and rises in carbon dioxide, extreme swings in climate and drastic effects on tropical vegetation.

"This is the best documented record we have of what happens to the climate system during long-term global warming following an ice age," said Isabel Montañez, professor of geology at the University of California, Davis, and lead author on the paper. But she added that these findings cannot be applied directly to current global warming trends.

In the mid-Permian, 300 million years ago, the Earth was in an ice age. Miles-thick ice sheets covered much of the southern continent, and floating pack ice likely covered the northern polar ocean.

Women who become pregnant in spring are more vulnerable to preterm birth than those who conceive in other seasons, according to researchers at the University of Pittsburgh.

Also, read Scientific Blogging columnist Seth Robert's interview with Brian Wansink here.

Researchers at Canada's National Institute for Nanotechnology (NINT) are learning which molecular scale factors affect the assembly and disassembly of microtubules that are part of a cell's skeleton. Microtubules control the division of all cells with a nucleus by constantly assembling at one end while they disassemble at the other.

While government leaders argue about the practicality of reducing world emissions of carbon dioxide, scientists and engineers are seeking ways to make it happen.

One group of engineers at MIT decided to focus its work on the nanostructure of concrete, the world's most widely used material.

Virginia Tech researchers in computer science and biology have used the university's supercomputer, System X, to create models and algorithms that make it possible to simulate the cell cycle -- the processes leading to cell division. They have demonstrated that the new mathematical models and numerical algorithms provide powerful tools for studying the complex processes going on inside living cells.