Articles by: Phil

Introductory Sections (for a Paper or Your Thesis)


By November 18, 2009 0 comments Uncategorized

Long-term Experiments

I recently read this Nature article, where is described what is probably one of the longest experiments ever to be conducted. A population of E. coli was kept for 20 years (!) in a nutrient solution (low on glucose), and samples were taken and deep-frozen after 2000, 5000, 10000, 15000, 20000 and 40000 generations. The authors sequenced the genome of the sample bacteria to investigate the rate of mutations.

Up to generation 20K, the number of mutations grew steadily to a total of 45. The adaptation to the environment, however, only increased strongly in the beginning. It was concluded that the most beneficial mutations were the first to occur. After generation 20K, a change in the mutT gene caused a rapid increase in the mutation rate to result in 653 mutation at generation 40K, but with a neutral signature, i.e. no further adaptation.

What I find most fascinating about this extreme long-term experiment is the confidence of the researchers that it would be possible to analyze the genes at a later point; this was not at all self-evident in the late ’80s! In addition, some work had to be done each day, for twenty years. What if the power had failed for a week or so? Of course, this unique opportunity to watch evolution as it happens is very intriguing.

An experiment that took even longer was awarded this year’s Ig Nobel Prize in medicine: Donald L. Unger of Thousand Oaks, CA, cracked the knuckles of his left hand, but not his right hand, every day for 50 years to see if knuckle-cracking leads to arthritis. After this time, both hands were fine, so he concluded: “While a larger group would be necessary to confirm this result, this preliminary investigation suggests a lack of correlation between knuckle cracking and the development of arthritis of the fingers.” Apparently, the experiment must be repeated.

By October 23, 2009 2 comments Uncategorized

Vice President of Research resigns at ETH

Another case of scientific fraud has been uncovered, unfortunately at my home university, ETH Zurich.

Quote from the official e-mail: “More than ten years ago, as has just been confirmed by an internal investigation, research data was falsified in a research group then headed by Peter Chen, who is now Vice President Research and Corporate Relations. It would be extremely difficult to find out exactly who manipulated the data.”

As a consequence, Chen steps down as head of research of ETH at the end of the month. He will continue working as a professor.

Apparently, somebody in his group had falsified spectra, which was proven by a repeating pattern in the background noise, as well as by the fact that the results could not be reproduced. The spectra were obtained by “zero-kinetic-energy photoelectron spectroscopy” of hydrocarbon radicals. At the time a doctoral student and a postdoc were involved in the project, however, the lab books and some raw data are missing. The two publication in question were withdrawn. Additionally, the student withdrew his doctoral thesis, but retracted the withdrawal later. As of now, it has not been possible to prove the guilt of a specific person, and all people involved deny falsifying the data.

By September 21, 2009 2 comments Uncategorized

Leaving the Lab

After 3+ years of manual labour (not counting undergrad studies) it is time to leave the hood and write up the thesis. I must say, it’s been a very good time, with good colleagues in the lab and also some reasonable results. I now have about two weeks left to finish the stuff that I’m currently working on.

After all this time, it will feel strange to leave my workspace behind and move to a desk. I know my hood so well, the way all the labware is sorted, that I could probably set up a column blind-folded. Time to move on! From now on, I’ll be spending my days in front of the computer screen. In the beginning, I expect the paperwork to be a nice change, but I’m pretty sure that it will get boring really quickly. For my future career, I cannot imagine having a desk job, although I’m sure the point will come where I’ll have no choice. The writing time will give me a taste of that future.

Looking back, somehow I feel that I have not accomplished very much during my PhD. It seems to me that I could have obtained the same results in much less time. Some of the problems I encountered now seem pretty trivial to me, so I ask myself why I spent so much time on them. I guess it’s always like that in retrospect…

Anyway, I’ll add a picture of a kitten (taken from here).

Graduation Cat
By August 17, 2009 6 comments Uncategorized