Monthly Archives: January 2006

Too Many Classes

It has become apparent to me that I’m taking too many classes. I’m going to drop one tomorrow or the next day. The homework is swamping me, and I’m not getting any research done. This is also why I haven’t been posting much lately — no time to spare for the blog. I’ve been unsubscribing from RSS feeds like mad. I even unsubscribed from Scoble. It seems like more and more of the same, now that I’ve been reading it for a while. I almost unsubscribed from Gapingvoid too, but not yet.

Any blog that I skip entries from repeatedly is being cut. Strangely, my LiveJournal feeds are the ones I read, and look forward to, the most.

Article Review: Reentry in heterogeneous cardiac tissue described by the Luo-Rudy ventricular action potential model by K.H.W.J. Ten Tusscher and A.V. Panfilov

Hubmed Page: Reentry in heterogeneous cardiac tissue described by the Luo-Rudy ventricular action potential model (with abstract)
The primary focus of this article is the effect of a gradient of action potential duration (APD) on spiral wave dynamics. The authors ran several simulations of a spiral wave using the Luo-Rudy I ionic model, and tracked the drift of the spiral wave’s phase singularity with respect to a gradient of APD. As the abstract says, spiral wave drift was in the direction of longer rotation period (analogous to longer APD, in this case), which is right in line with what should be expected. Higher-frequency rotation should push the spiral wave center (phase singularity) away, regardless of the phenomenon underlying that higher frequency. The article is a medium-length read at six pages. While it seems somewhat redundant, in that every test yielded approximately the same results, this leant strong support to the conclusions of the paper — no caveats or qualifications were necessary. The conclusions of this article are important to the study of arrhythmias in regional disease, where gradients of electrophysiological disease exist along the borders between normal and diseased tissues.
The paper does not, unfortunately, delve into the details of why high-frequency rotation pushes away low-frequency rotation. A similar phenomenon was explained to me this past fall by Dr.Valentin Krinski with regard to two interacting spiral waves or periodic sources. I’m currently struggling to find the bridge — the relationship between different frequencies in different parts of the same spiral wave, and different frequencies in different spiral waves.

If you know why this is, kindly leave a comment. In the mean time I’ll be puzzling over it.

White House secrecy

“The Bush administration, citing the confidentiality of executive branch communications, said Tuesday that it did not plan to turn over certain documents about Hurricane Katrina or make senior White House officials available for sworn testimony before two Congressional committees investigating the storm response.” Eric Lipton, White House Declines to Provide Storm Papers, New York Times, 25 January 2006

What is with these guys that everything is some kind of state secret?

(This posting from Kodjo also appeared on Catallaxy)