Wednesday, March 09, 2005

Open Access ACS

The American Chemical Society, the largest professional scientific society in the world with 158,000 members, announced today that it will be expanding access to articles in all of its 33 journals. One year after publication, ACS will post manuscripts on the National Library of Medicine's PubMed Central, a free digital archive. This is in response to this new policy from the NIH:
Beginning May 2, 2005, NIH-funded investigators are requested to submit to the NIH National Library of Medicine's (NLM) PubMed Central (PMC) an electronic version of the author's final manuscript upon acceptance for publication, resulting from research supported, in whole or in part, with direct costs from NIH.

ACS Journals are not the first publicly available scientific journals, but this addition is significant due to their prestige in the chemical community. ACS Publications Division President Robert Bovenschulte, had this to say:
These experimental policies balance the important goal of expanding dissemination of research with the need to preserve the integrity of the scientific record as well as the viability of our journals program.

Let's hope these experiments work. Now go read some chemistry.

Tuesday, March 08, 2005

Sticky Ice

The origin of planets, their orbital irregularities, and their differences in chemical composition has confounded astronomers for hundreds of years. A new theory put forth in the Astrophysical Journal has a very interesting take on this classical problem.

Pre-planetary dust was covered, or composed mostly of, frozen water. When water freezes at normal temperatures and pressures on our planet, you get a hard inelastic substance. This is not the only form that solid H2O can take though (remember Ice-9?). The diagram on the left shows some of the different phases that solid H2O can take as a result of pressure and temperature.

This recent publication from scientists at the Pacific Northwest National Lab studies ice produced at temperatures between 5 and 100 Kelvin. The ice produced at these extremely low temperatures is rather different from the stuff used to chill martinis. This solid can become spontaneously polarized - an electric force that allows this sticky ice to clump together.

To demonstrate the elasticity (read: stickiness) of this form of ice, the authors measured the rebound of a ceramic ball bouncing off of a surface of normal ice-cube ice, and their extremely cold sticky ice. The ceramic ball rebounded to 80% of the drop height when bounced off of normal ice, while that height was diminished to only 8% when the sticky ice was used (image shown at right), demonstrating that ice particles (at pre-planetary temperatures) could have run into other ice particles to form clumps. This clumping of ice and dust eventually, apparently, leads to planet formation.

For background on classical theories of planet formation see this entry in the Columbia encyclopedia.

Via: EurakAlert!