Monday, November 28, 2011

An amazing video....

on the effects of forming sea ice on organisms living on the ocean floor (who would have thought?)
Given that part of the purpose of this blog is to remind me of what I have read and thought, I can report that I finished the Flavia De Luce mystery "I Am Half-Sick of Shadows" as well as Andrew Knoll's "Life on a young planet".  As I was reading Knoll's book, I realized that the section in Biofundamentals on endosymbiosis and the origin of eukaryotes was rather too sketchy, so I revised it.  Knoll's book reminded me of the historic origins of the endosymbiotic hypothesis, in the late 1800 and early 1900s.  

Amazingly, as I was writing the death of Lynn Margulis was announced.  Her major contribution was returning the idea of the endosymbiotic origins of mitochondria and chloroplasts (seem was clearly wrong about flagella).  As is often the case in the popular press, description of her contribution seemed to be inaccurate, exaggerated, and overly-dramatic; endosymbiosis is a perfectly Darwinian (that is biological) mechanisms for evolution.   

As to Knoll's book, which appeared in 2003, I am left (as I often am) concerned about the need to hype the relatively minor contributions of specific people, when in fact the lesson of science is that, more often than not, it is the churning of ideas and observations by the community that separates solid and meaningful insight from mistakes and trivia. I cannot help by hold my head when people talk about life on Earth originating from Mars.  

Wednesday, November 23, 2011

brains and free will and living science

Here is a very interesting interview with Michael Gazzaniga who works on split brains and how brain work.  Also reflects my experiences at CalTech, namely the importance of caring (primarily) about the science compared to secondary concerns about one's career.  

Here is a interesting lecture on the Mind-Brain System

Wednesday, November 16, 2011

cell phones + microwaves + cancer

from Bob Park's newsletter:

Of the world’s 7 billion people, an incredible 5 billion have cell phones 
(“mobiles” in most countries).  The safe use of mobiles is therefore a 
global health concern. The response of the World Health Organization was to 
conduct a huge epidemiologic study aimed at demonstrating a link between 
cell-phone radiation and brain cancer.  The effort was seriously misguided –
no such link exists.  The study served only to raise widespread public 
alarm over a nonexistent hazard.  Epidemiology, which is the study of 
health patterns in populations; is important, but it’s not a substitute for 
science.  Science is the organization of knowledge into testable laws and 
theories.  It has been known for more than 100 years that electromagnetic 
radiation at frequencies below the ultraviolet is non-ionizing, and thus 
cannot create the mutant strands of DNA that constitute incipient cancers.  
In 1905, Einstein’s “miracle year,” he theorized that electromagnetic 
radiation consists of discrete units of energy, now called “photons,” which 
are equal in energy to the frequency multiplied by Planck's constant. It 
marked the origin of wave-particle duality and earned Einstein his 1921 
Physics Nobel Prize.  His theory is verified every time a cell phone 

Friday, November 11, 2011


What great discussions in today's class, but as to the discussion of colorblindness, I have to admit I am befuddled. The national institutes of health (NIH) websie suggests that

"Expectations (prognosis)

Color blindness is a lifelong condition. Most people are able to adjust to it without difficulty or disability."

I will keep checking...

Saturday, November 05, 2011

Shouldn't politicians (and people who seek office) be scientifically literate?

Congratulations to Michael Bloomberg [link] for saying what anyone with a brain, and an education, and a backbone should say.  

Tuesday, November 01, 2011

DNA stretching by origin recognition protein

In E. coli (and other bacteria), the origin of replication (known as oriC) is recognized by the DnaA proteins.  In this recent paper in Nature [here], structural studies show that the binding of DnaA molecules to the oriC DNA region leads to the stretching of the DNA molecule, and the stabilization of single stranded DNA, which appears to be part of the process for assembling the DNA replication complex. Yet another cool molecular machine.

The red structure is the single-stranded DNA, the other colors are the proteins.  Can you determine whether DnaA is primarily composed of beta-sheets or alpha-helices?