Saturday, March 15, 2008

Ginkgo and placebo stories

Two news stories I read today about recent research.

In the first they found evidence that Ginkgo biloba extracts protected the memory of people 85 and older. The three-year study involved 118 people age 85 and older with no memory problems. Half of the participants took Ginkgo biloba extract three times a day and half took a placebo. During the study, 21 people developed mild memory problems, or questionable dementia: 14 of those took the placebo and seven took the ginkgo extract.

Once they controlled for patients who did not reliably take the pills they found a significant effect. However
people taking Ginkgo biloba were more likely to have a stroke than those taking the placebo. Seven people taking ginkgo had strokes, while none of those taking placebo did.

And speaking of placebos. The LA times reported on research showing that placebos work better if they cost more. Test subjects were given a placebo they were told was a powerful pain medication. Half of the subjects were told the medicine cost $2.50 a pill while half thought it cost 10c. 85% of those receiving the 'higher priced' pill reported feeling less pain from an electric shock after taking the pills versus 61% of those getting the 'cheaper' pills.

Wednesday, March 12, 2008

Cretaceous-Tertiary exctinctions

I just noticed that today's featured article on Wikipedia is the Cretaceous–Tertiary extinction event. I just read it and it is a very fine article indeed. Featured articles at Wikipedia are considered to be the best articles and undergo a fairly comprehensive review process to make the cut. If you make the Wikipedia main page your home page and make a point of scanning the featured article everyday you can learn a lot of, well, stuff basically. An awful lot of stuff.

Animal cladogram

I added a cladogram for the animal groups we discussed as the last slide on the lecture 16 powerpoint (in the links menu to the right). It is a very useful exercise to go though and add the twelve listed synapomorphies and circle the seven additional named taxa. Not required, not assessed, just useful.

Wait, turn that tanker full of iron around

Startling Discovery About Photosynthesis: Many Marine Microorganism Skip Carbon Dioxide And Oxygen Step

Certain marine microorganisms have evolved a way to break the rules--they get a significant proportion of their energy without a net release of oxygen or uptake of carbon dioxide. This discovery impacts not only scientists' basic understanding of photosynthesis, but importantly, it may also impact how microorganisms in the oceans affect rising levels of atmospheric carbon dioxide. ScienceDaily (Mar. 12, 2008)

Tuesday, March 11, 2008

It's hard to be a weed in the city

Three stories from New Scientist Magazine this week. I've said it before and I'll say it again, it's good value for $60 a year for a weekly magazine. And no, I still don't get a kick-back.

  • Surrounded mostly by concrete rather than fertile soil, urban weeds have evolved - in just a dozen generations - to keep their seeds close to home.
  • It has long been assumed that the eyespots of butterflies and moths tap into just that fear, but the true function of such wing patterns might be much simpler.
  • It was only the size of a mouse, but it has the distinction of being the first primate to scurry into the New World.

Wait, wait. A mouse sized monkey? Forget the Zonkey, I want a mouse sized monkey.

Monday, March 10, 2008

Don't forget

Don't forget to get the list of topics you investigated to me or Claudia today. You will write on one of these tomorrow and present one (your choice) orally on Thursday.

NOTE (because the comments aren't always obvious): There are 21 of you and about 65 minutes left after we do the obligatory evaluations. You do the math. That's 3 minutes MAXIMUM. Aim for 2 1/2. You can't cover much but you can say what you investigated, why you found it interesting and maybe one interesting thing you discovered. Short and sweet. Good practice.

Sunday, March 9, 2008

In Science this week is news that 80 million years ago sea levels were roughly 560 feet (170 meters) higher than they are today. Science have news report on the story (which will link to the paper if you are on a campus computer or using the library proxy).

In the age of the dinosaurs, great inland seas kept the climate balmy and redirected the course of evolution by opening huge new niches. But these seas weren't constant, and scientists have long debated how high they rose and why. A new study finds that global sea level was 170 meters higher than today and chalks the dynamism up to an ever-changing sea floor.

Friday, March 7, 2008

Sea Center

I'm not sure if this was mentioned or not, but in case you don't know the Santa Barbara Museum of Natural History also runs the Ty Warner Sea Center on Stearns Wharf in downtown Santa Barbara. As well as checking out the exhibits sometime this is another place you might consider volunteering.

Thursday, March 6, 2008

Stop-motion


Remember this movie was pre-cgi and so it was made using the stop-motion animation technique. (Well, Raquel Welch was real, although not necessarily realistic). Ray Harryhausen was the master of this technique and single handedly kept it alive for over 30 years. His masterpiece is usually considered to be the skeleton fight in the movie Jason and the Argonauts.

Permian extinctions

I came across this interesting paper in a Geological Journal in 2005 that outlines a theoretical argument for how hydrogen sulphide might have been responsible for the Permian extinction event (Massive release of hydrogen sulfide to the surface ocean and atmosphere during intervals of oceanic anoxia).

Simple calculations show that if deep-water H2S concentrations increased beyond a critical threshold during oceanic anoxic intervals of Earth history, the chemocline separating sulfidic deep waters from oxygenated surface waters could have risen abruptly to the ocean surface (a chemocline upward excursion). Atmospheric photochemical modeling indicates that resulting fluxes of H2S to the atmosphere (>2000 times the small modern flux from volcanoes) would likely have led to toxic levels of H2S in the atmosphere.

What I thought was interesting is that paper just predated the biomarker evidence I mentioned in class. They add this note in at the end of the paper:
Note Added in Proof: Biomarker evidence consistent with the hypothesis of chemocline upward excursion at the Permian-Triassic boundary has just been reported online in Science Express (Grice et al., 2005).
It must be kind of cool to have evidence for your theory come out just as your paper is being published.

Or maybe it was an asteroid. This is the recently discovered asteroid impact evidence I was trying to remember. It was from 2006. Scientific American had a 2006 article that reviewed the evidence for the alternative, although not necessarily mutually exclusive, theories.

Tuesday, March 4, 2008

Crater animation

Click the image for a crater formation animation. This is from a nice website on the discovery of the Chicxulub crater - subsequent to the theory that an asteroid had impacted at the K-T boundary. The page on the discovery of the impact site is interesting but also check out the pages on the regional and global impacts.

On a different page you can see an animation of the wildfires caused as the ejected debris rained back down to earth.

Sunday, March 2, 2008

Next quarters Biology Class

Is next quarter's class up on gold yet?  If it is, what is the class number?  
Thanks everybody