On Tuesday I experienced my first California earthquake. After the first wave I thought: Oh, a cute little earthquake! Then I realized that a bigger wave would be coming. And it did: it was like being in the wooden house of the second pig, while the wolf huffed and puffed from outside.
The magnitude was 5.4 and the epicenter was very close to here:
I also discovered that Richter was a Caltech professor, and Caltech monitors earthquakes for all California (altough they don’t use the Richter magnitude scale anymore, but something called the moment magnitude scale). In the hours after the quake, there were lots of media trucks around:
The Caltech monitoring system sent me an email containing a wave file (?). Maybe they thought that a female voice helps in tranquilizing people.
I also received this email from the administration:
Caltech had no injuries. We had some chemical spills that required temporary evacuation in at least one building. We had minor damage, including broken water pipes in Noyes and in the Cogen plant. Four elevators went temporarily off line. The campus responded as you would have hoped. Everyone did their part – from the daycare center to the environmental health and safety group, facilities, computing and telecommunications, to individuals in all the buildings and labs, and to HR for the notice to be thoughtful of those employees whose homes were closer to the epicenter.
I assume that it was by coincidence that, at the time of the earthquake, the Caltech Trustees were being given a tour of the Seismological Lab. I am told that they were impressed. Public Relations and the Seismo Lab must have been busy. I counted 10 media trucks parked outside as I left campus last night.
Best demo ever!
My 4-year-old iPod mini died yesterday in a tragic incident involving a moth and a cupful of coffee. It survived a couple of traumatic crashes on the floor, and two surgical procedures: I opened it once for replacing the battery, and again to fix a loose headphone connector.
This last problem was difficult (i.e., fun) to diagnose. One day I realized that all the songs on my iPod had become instrumental pieces: I couldn’t hear the singers voice anymore! A little experimentation suggested that, somehow, a certain band of frequencies were absent from the output: the same band that contains the human voice singing range (say 440-1000 Hz). For some songs, like Still Alive the effect was particularly clean as the spectrogram of voice and harmony is clearly separated.
Now this looked like a typical software problem: somehow the equalizer’s settings had been messed up. I tried resetting the firmware, but the problem persisted. So I resolved to open it. From what I could guess, the mp3 decoder in the iPod is constituted by several different ones, and each of them takes care of a certain range of frequencies. These decoders output their signal to a common digital-to-analog converter, from which the headphones line starts. The decoders and the DAC are not on the same chip, rather the DAC is a separate component just behind the headphones jack. Part of the wires were loose, and so part of the frequencies couldn’t be heard.
_______
|f1|-------> | |
|f2|-------> | |
|f3|-------> | DAC | ----> headphones
|f4|--x----> | |
|f5|--x----> | |
| -------
\
loose wires
So the diagnosis was that the wires got loose when I last dropped the iPod on the asphalt while I was running, and the fix was to insert a little piece of plastic in the connector.
I’m shopping around for a new iPod, and in four years there has been a lot of improvement in the form factor and the aesthetics. Unfortunately, the more compact they get, the less “user serviceable” they are, meaning that if it doesn’t work, you just throw it away, without any chance of fixing it yourself.
I moved out of my old apartment.
It was probably the worst in the Catalina complex. It was on the ground floor, in the shadow, on the street, near the garbage bins. Every day I woke up at nine because of the noise of the garbage men. (Descartes used to say that good mathematics is possible only if one is allowed to stay in bed as much as he wants, and who am I to disagree?)
This new apartment is a two-bedroom, instead of four.
Accordingly, I went from 3 physicists room-mates to only one, who is a swiss-italian-american nuclear physicist who likes Rubik cubes:
It’s sooo Caltech! (Did you know that probably the most famous cuber — for having partecipated in The beauty and the Geek, no less — was a Caltech student? And did you know that twenty-six moves suffice?)
