In October of ’07, I posted about my move to Google Notebook as my primary lab notebook. It has not only continued to serve me well since then, but now serves me even better with the addition of a few features:
- Auto-dated notes: I’d be happier if I could opt for auto-timestamps as well, but Google now adds the date a note was created (not sure if it updates it when edited but I don’t think so) to the upper right-hand corner. Now instead of putting the date and location at the top of each note, I just put the location.
- Sharing: It’s now easy to share with others. I’ve shared my notebook with my advisor so that she can follow along if she likes. I used to do this on our lab wiki as well. It would also be possible to have a shared notebook between all of the people on a project, almost like a private blog. I think this latter use has a lot of potential
- Labels: Google has added labels (in practice the same thing as ‘tags’), making it possible to tag each entry with the projects to which it is related. Pulling up all of the notes on a project is then as simple as selecting the appropriate label.
It keeps getting better. Hopefully, they will add those automatic time stamps at some point.
My friend Rob has another excellent mathematical post up. It has, in fact, been up since December 14th, but I’m only now catching up with my starred RSS items from last month.
This post is on the nature of infinity and other large numbers, and how we mentally relate to and handle them. Here’s a taste:
[I]f you look at infinity from a size standpoint, infinity is dizzyingly terrifying. Most people don’t have a proper concept of what “large” means, but mathematicians know better:
- The universe is 13.7 billion years old, or 4.3*10^-17 seconds. Current quantum theory has trouble measuring time below Planck’s time constant, or 1.855Ã—^-43 s. If we treat the idea of time as a discrete number of Planck’s constants, then the age of the universe is 8*10^60 of these constants. Infinity is bigger than this.
- The number of atoms in the universe is estimated to be around 10^80.
- The biggest number ever seriously used in mathematics is Graham’s number. The number is an upper bound for some mathematical property. The number is so huge that it cannot be written with scientific notation (the exponent would have more digits than atoms in the universe). Still, infinity is bigger than this number.
- The Ackermann function is a strange non primitive recursive function:
This function generates huge finite numbers. For example, A(5,2) is so large that it cannot be describing it with common math notation would take more letters than there are atoms in the universe (this includes 9^9^9^9^9^9… etc.). Still, infinity is bigger than this number.
Read the whole thing here.
In this article
, a boy was struck by lightning at lacrosse camp, given CPR and defibrillated three times with an AED
, and eventually made a full recovery.
Amazing. AEDs continue to come down in price, and are really racking up an extensive list of saved lives.
I’ve gotten a lot of strange looks over the last two or three years because of how I carry my cards and cash. I abandoned wallets of any kind because they either (a) more than double the volume of what I’m carrying or (b) they have too much stuff in them. That is, if there’s enough in them that they don’t double the volume, it’s too much and sits funny in my pocket.
Luckily, I found the solution with cheap and plentiful office supplies. (Please note, I will show you that the Money Band and its cousins are both unnecessary and way overpriced. They are akin to pet rocks.) All you need are a thick rubber band of a certain length, and a paperclip. Any size paperclip will do, but the larger ones work better.
Money Bands: $0.60 each
Rubber Bands: $0.016 each
Jumbo Paper Clips: $0.006
Or, look at it this way:
Money Band: 1-year supply for $3.00
Paper Clips / Rubber Bands: Lifetime supply for you and all of your friends for $10.30
I think the choice is clear. The way of wrapping the rubber band that I use is also superior. It’s also nice not to have to take out everything at once — just the money or the cards. The two don’t really fit together properly, even with a Money Band.
Good to see that he tells it like it is — you won’t hear any mention of this stuff from the administration at Tulane, you’ll just hear a pile of euphemisms, but we (who were or are there) know it to be true: