Meeting My Sciblings

This weekend, Seed Media, our benevolent and beloved corporate overlords, sponsored a Scibling gathering: ScienceBloggers from all over the country (and outside) all gathered in New York, ate, drank, and partied.

It made for quite an interesting weekend. I didn’t end up being able to hang around nearly as much
as I would have liked (I missed the drunken Karaoke! As someone who never gets drunk, watching
my drunken sciblings singing badly would have been a kick!) Alas, as the father of two small kids,
I’m subject to the schedule of family/babysitters, so I couldn’t hang aronud. (Plus, to make matters worse, my wife became sick friday night, and I started feeling sick saturday afternoon. I’m writing this from bed.)

But I did manage to meet quite a lot of folks, even in my limited time there. It’s quite an odd experience in its way; between our blogs, and our back-channel forums, we’ve become a tight-knit community, and the people there were my friends, even though I’d never seen them before. It
was a whole lot of fun. My impressions are below the fold. They’re just off the top of my head; I’ll probably edit this
later as I remember more.

By the way, that ScienceBlogs mug that Seed is offering to give away in the subscription ads? They gave us each one as a gift, and theyre great. It’s a very nice, heavy glass mug that looks like a cross between a mug and a beaker.

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Friday Random Ten

  1. Sonic Youth, “Or”: Very smooth for SY. But great. They’re an amazing band.
  2. The Flower Kings, “Blue Planet”: A typical track from one of my favorite neo-progressive
    rock bands. For the Flower Kings, this is a short one at only 10 minutes.
  3. The Clogs, “Lantern”: once again, one of my favorite classical-leaning post-rock bands. Slow,
    beautiful track, featuring steel drums and oboe, and even some light vocals.
  4. Mariliion, “Fantastic Place”: one of my least favorite tracks from an amazing Marillion
    album. Overall, the “Marbles” album was fantastic, but this track just leaves me cold.
  5. Darol Anger’s Republic of Strings, “Higher Ground”: quite a change from the last
    couple. Very up-tempo jazzy string-ensemble cover of a Stevie Wonder tune.
  6. The National, “Baby We’ll Be Fine”: The National are the alter ego of the Clogs; they’ve got
    nearly the same personnel. But the National is a slightly country-ish alt-rock band. This track
    has a great psuedo-minimalist melodic pulse under it. Very cool.
  7. Naftule’s Dream, “Free Klez 1 & 2”: what happens when a group of really talented klezmer
    musicians try to an Ornette Coleman style free improv? Weird stuff.
  8. Navan, “Thig an T-Eathor”: very traditional a-capella Irish songs. Not what you’d probably
    expect if you’re used to instrumental Irish; songs are a totally different form
  9. Mark Knopfler, “Boom, Like That”: The guitar wizard of Dire Straights has been doing mostly
    solo work lately. This is a track from his latest solo album, about (of all people) Roy Kroc, founder
    of McDonalds. Good song, with a nice guitar hook.
  10. Marillion, “Ocean Cloud”: another track from Marillion’s “Marbles” album – this one is an
    example of just why I like this album so much: it’s an 18 minute long opus, just terrific stuff.

Bad Homeopathic Differential Equations. Yech.

My friend and blog-father Orac sent me a truly delectable piece of bad math today. It’s just
astonishing: a supposed mathematical model for why homeopathic dilution works, and for why the
standard dilutions are correct. It’s called “The octave potencies convention: a mathematical model of dilution and succussion”, and I got a copy of it via the Bad Science blog. The only part of it that’s depressing is the location of the authors: this piece of dreck was published by someone from the Harvard medical school.

To give you an idea of what you’re in for, here’s the abstract:

Several hypothesized explanations for homeopathy posit that remedies contain a concentration of discrete information-carrying units, such as water clusters, nano-bubbles, or silicates. For any such explanation to be sustainable, dilution must reduce and succussion must restore the concentration of these units. Succussion can be modeled by a logistic equation, which leads to mathematical relationships involving the maximum concentration, the average growth of information-carrying units rate per succussion stroke, the number of succussion strokes, and the dilution factor (x, c, or LM). When multiple species of information-carrying units are present, the fastest-growing species will eventually come to dominate, as the potency is increased.

An analogy is explored between iterated cycles dilution and succussion, in making homeopathic remedies, and iterated cycles of reseeding and growth, in bacterial cultures. Drawing on this analogy, the active ingredients in low and medium potency remedies may be present at early dilutions but only gradually come to ‘dominate’, while high potencies may develop from the occurrence of low-probability but faster-growing ‘mutations.’ Conclusions from this model include: ‘x’ and ‘c’ potencies are best compared by the amount of dilution, not the amount of succussion; the minimum number of succussion strokes needed per cycle is proportional to the logarithm of the dilution factor; and a plausible interpretation of why potencies at approximately regular ratios are traditionally used (the octave potencies convention).

What you find in this paper is both an astonishingly bad example of mathematical modeling, and
a dreadful abuse of differential equations. It’s pathetic to realize that anyone thought
that this piece of dreck was not too embarrasingly bad to publish.

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A Bid to Shut Up the Religious Bigots

This post is quite thoroughly off-topic for this blog. But as someone who is openly religious and who
has written a number of posts that criticize Christian institutions, I get a fair bit of mail from cretins
who make demands that I speak up to defend their pathetic insistence that all religious people
must support discrimination. In the hopes that I can get these jackasses to leave me alone by
demonstrating that I’m so far beyond the pale that pestering me is a waste of time, I present this
post.

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Representing Graphs

One of the reasons that I like about graph theory so much is because of
how it ties into computer science. Graphs are fundamental to many problems in
computer science, and a lot of the work in graph theory has direct implications for
algorithm design. It also has a lot of resonance for me, because the work I do involves
tons and tons of graphs: I don’t think I’ve gotten through a week of work in the last decade without
implementing some kind of graph code.

Since I’ve described a lot of graph algorithms, and I’m going to
describe even more, today I’m going to talk a bit about how to represent graphs
in programs, and some of the tradeoffs between different representations.

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Traversing Graphs

One amusing thing in graph theory is graph traversal. Many of the interesting algorithms on graph
are ultimately based on the idea of iterating through the nodes of the graph in some order that is
related to the structure of the graph.

There are two fundamental orders of graph traversal, known as breadth-first and depth-first.

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The Problem with NFL: Breadth or Depth?

Despite having written about it before, I still get a lot of questions about William Dembski’s “No Free Lunch”
(NFL) theorems. One message recently contained the question in a particularly interesting form, so I thought I’d take
the opportunity to answer it with a post.

Here’s the question I received:

  1. Is the NFL theorem itself bad math?
  2. If the theorem itself is sound, what’s wrong with how it’s being applied? Is it a breadth issue
    or a depth issue?

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Shortest Paths and Greedy Relaxation

Another really fun and fundamental weighted graph problem is the shortest path problem. The
question in: given a connected weighted graph G, what is the shortest path between two vertices
v and w in G?

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Bad Math Education: Math does not need God

Once upon a time, I wrote about a jackass who was criticizing his college math instructor, because the instructor couldn’t explain what made the calculus class christian, or why it was different from what would be taught in a math class at a secular college.

That kind of thinking is quite strong in certain segments of the conservative christian community, and that disgusts me. Let me show you an example, and then I’ll explain why is annoys me so much. A reader
send me a link to the math curriculum for a Baptist high school, and it seriously bugs me.

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Fractal Dimension

pink-carpet.png

One of the most fundamental properties of fractals that we’ve mostly avoided so far is the idea of dimension. I mentioned that one of the basic properties of fractals is that their Hausdorff dimension is
larger than their simple topological dimension. But so far, I haven’t explained how to figure out the
Hausdorff dimension of a fractal.

When we’re talking about fractals, notion of dimension is tricky. There are a variety of different
ways of defining the dimension of a fractal: there’s the Hausdorff dimension; the box-counting dimension; the correlation dimension; and a variety of others. I’m going to talk about the fractal dimension, which is
a simplification of the Hausdorff dimension. If you want to see the full technical definition of
the Hausdorff dimension, I wrote about it in one of my topology posts.

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