Please create an account to participate in the Slashdot moderation system


Forgot your password?

Slashdot videos: Now with more Slashdot!

  • View

  • Discuss

  • Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

User Journal

Journal: Wax esters: Adaptation for colonization of the earliest terrestial environments?

Journal by Group XVII

Wired Science reports:

The earliest microbes that survived on land may have synthesized fat molecules to prevent their death from dehydration.

The molecules, called wax esters, could have helped the microbes colonize land by protecting them against the harsh environments that probably characterized the lifeless continents, scientists hypothesizes in the March issue of Geology .

"Production of [wax esters] may represent an adaptation to cross a critical evolutionary threshold, i.e. surviving dehydration and/or dessication cycles," wrote David Finkelstein, a biogeochemist at the University of Tennessee-Knoxville, and his co-authors. "This adaptation could have facilitated bacterial migration into the earliest lakes, and aided survival in terrestrial environments."

Little is known about early terrestrial microbial life, which probably colonized land sometime before 500 million years ago. Unlike animals, they don't leave behind much that scientists can find. But these organisms prepared the way for more complex life by seeding the land with organic compounds that became soil.

The report continues....

User Journal

Journal: An Estimated 15% of Stars in the Milky Way Have Planetary Systems Like Our Own

Journal by Group XVII

Centauri Dreams is among those reporting from the American Astronomical Society meeting in Washington. They say:

Right now Scott Gaudi's talk on Tuesday is generating the biggest buzz. Gaudi (Ohio State) reported on a gravitational microlensing effort called MicroFUN (Microlensing Follow-Up Network), one we've previously discussed in these pages. The method is well understood: One star occults another as seen from Earth. The light of the more distant star is magnified by the nearer one, and any planets around the lensing star momentarily boost the magnification as well. You find planets this way, though they're not planets likely to be observed again because of the nature of the method.

I love this Gaudi quote from the talk: "Planetary microlensing basically is looking for planets you can't see around stars you can't see."

Gaudi's team has concluded that about fifteen percent of the stars in the galaxy are orbited by planetary systems like our own, meaning they have several gas giants in the outer part of the solar system. That fifteen percent is telling. "Solar systems like our own are not rare," says Gaudi, "but we're not in a majority, either." Microlensing is useful for this kind of study because the method does a good job at picking up giant planets far from their primary star, a more difficult task with Doppler methods.

The full discussion is here. Also reporting are Space.Com and Science Daily and Universe Today.

User Journal

Journal: Nyamuragira Continues to Erupt

Journal by Group XVII

Mount Nyamuragira in Virunga National Park continues to erupt for a fourth day. Cases of cholera are being reported from nearby towns as the volcanic soot and ash contaminate drinking water. It hasn't yet been reported whether Virunga's mountain gorillas, currently facing extinction, are likely to suffer from the effects of contaminated food and water.

The Centers for Disease Control has prepared a fact sheet on the health effects of volcanic eruptions.

It is not for me to attempt to fathom the inscrutable workings of Providence. -- The Earl of Birkenhead