Science After Sunclipse

Mathification

Tue, 22 Jun 2010 09:26:23 -0500

Nostalgia time! Today's entry is reposted from June 2008.

Megan Garber writes the following in the Columbia Journalism Review's daily blog:

We currently find ourselves in, to put it mildly, a lull in the 2008 campaign's primary season. The delegate tallies are in limbo. Parsing them seems to require a postgraduate degree in calculus.

I call mathification! The analogue of linguification, this term refers to statements which, as God Plays Dice puts it, "clearly intend to get across a true point about the real world by making a false point about mathematics."

Read the rest of this post... |

Call for Papers: Adaptive Networks

Mon, 21 Jun 2010 10:00:00 -0500

Word came in the other day on the iGrapevine about a conference, set to happen in Boston this December. One track of Bionetics 2010, on adaptive networks, looks particularly interesting.

Complex network research has so far addressed mostly either "dynamics on networks" (state transition on a network with a fixed topology) or "dynamics of networks" (topological transformation of a network with no dynamic state changes). In many real-world complex biological and social networks, however, these two dynamics interact with each other and coevolve over the same time scales. Modeling and predicting state-topology coevolution is now recognized as one of the most significant challenges in complex network science.
This Special Track solicits theoretical, computational, experimental and/or application-oriented research on any aspects of the state-topology coevolution of complex networks—either biological, social, or engineered. Its goals are to promote the growth of a research community on this emerging new field of network research, to help develop a common conceptual "language" for modeling, analyzing and discussing the state-topology coevolution of various real-world complex adaptive networks, and thereby to galvanize interdisciplinary discussion and collaboration across many different areas of applications.

The session chairs are Hiroki Sayama and Thilo Gross, who recently co-edited an anthology on the subject. (COI disclaimer: Prof. Sayama gave me a copy at NetSci 2010, and I enjoyed reading it.) For more details, see the conference website. I mean, how could you pass up Boston in December?

Handwriting Priorities

Mon, 21 Jun 2010 09:04:19 -0500

Reposted from three years ago to test mathcache a bit more.

Zeno mourns that his calculus students can't read their own handwriting. Not only do their 2s become zeds, but their thetas become phis and their phis become rhos:

\[ \theta \rightarrow \phi,\ \varphi \rightarrow \rho. \]

Personally, it was the xi which always gave me trouble. That stupid little $\xi$ never came out right — and I know I'm not alone here. In that introductory string theory course of sainted memory, Prof. Zwiebach astonished our whole class by writing them freehand on the blackboard.

You know, in retrospect, I wish my elementary school had skipped the cursive lessons and taught me how to write Greek letters. Oh, and "blackboard bold" characters too, the funky symbols with extra lines like $\mathbb{R}$ and $\mathbb{C}$ (these particular ones are used to stand for the real and complex number sets, respectively). If your Greek alphabet is muddled — or, worse yet, if it gets mingled with your Latin letters — the result can be catastrophic. One fellow physics student, a couple years my junior, told me how he found himself stumped by an answer which kept coming out wrong by two orders of magnitude. Neither he nor his professor could figure out what was going wrong, until he realized that he'd been substituting in the numerical value for the velocity, $v$, instead of the numerical value for the frequency, which in class had been written with a nu, $\nu$.

Or, as the classic "joke" has it:

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The snarXiv

Thu, 10 Jun 2010 12:01:40 -0500

When I was in high school, I used an early version of the Postmodernism Generator to do my Advanced-Placement English homework. (I'm hardly alone in thinking that "Transgressing the boundaries" was one of the funniest hacks ever.) I guess turnabout is only fair play, after all:

For those of you tired of the arXiv, why not try the snarXiv?

As its inventor explains,

The snarXiv is a random high-energy theory paper generator incorporating all the latest trends, entropic reasoning, and exciting moduli spaces. The arXiv is similar, but occasionally less random.

(Via Flip Tanedo.)

A Thought Occurs

Mon, 07 Jun 2010 09:01:28 -0500

Many of you have probably seen those "symphony of science" videos made by autotuning clips of various science-people. You know what I would find superlatively entertaining? If somebody would do the same thing with Sidney Coleman's quantum field theory lectures. Enough with the advertising; let's make an audiovisual event out of the real thing. The weird halo and tracer effects from the 1970s video equipment would be an added bonus. You could even make an instrumental break montage out of all the times Sidney lights up a cigarette.

"We found we could not define a satisfactory $ x $ operator [bwoop bwoop!]. When we tried, we found the particle moved faster than the speed of light [un-tss! un-tss!]."

"The sum of all Wick diagrams is the exponential of the sum of connected Wick diagrams [beep boop]."

Or, for a chorus:

"Theoretical physics is defined as a sequence of courses, each of which discusses the harmonic oscillator."

Symphony of Science: Graduate School Edition!

The Aphids Must Die!!

Thu, 03 Jun 2010 09:48:48 -0500

Drive the ladybug around the screen, eat the aphids and see how the aphid traits evolve.

(From the Bio/computational Evolution in Action CONsortium (BEACON) website, which I discovered through The Panda's Thumb.)

Resultant Modular Quantities are Serious Business

Wed, 02 Jun 2010 09:20:35 -0500

It's comforting to know that even the venerable personages of The Open University could make mistakes.

I hear the blooper reel for Walter Lewin's classical mechanics lectures are downright scandalous.

OPERA Sees Neutrino Oscillation

Mon, 31 May 2010 10:43:11 -0500

Happy news from Gran Sasso:

After more than three years of research and the passage of billion of billions of particles travelling from one part of the Alps to another, the metamorphosis of a neutrino has been directly observed for the first time ever, at the Gran Sasso National Laboratories of the Italian National Institute for Nuclear Physics (Istituto Nazionale di Fisica Nucleare - INFN) in Gran Sasso (LNGS). This metamorphosis consists of the transformation of one type of neutrino into another, a result that will pave the way for New Physics, although it will obviously have to be confirmed by additional observations of "mutating" neutrinos such as this first one.
The phenomenon was observed by the international collaboration OPERA (Oscillation Project with Emulsion-tRacking Apparatus). Neutrinos are "shot" from the European laboratory of CERN in beams directed to the Gran Sasso: in a mere 2.4 milliseconds they travel 732 kilometres beneath the Earth's crust to the core of the Gran Sasso Mountain in the Abruzzo Region and, during their journey, there is the possibility that some of them "change" their nature. [...] For 15 years a number of experiments have revealed the neutrino oscillation through disappearance of neutrinos coming from the atmosphere, the Sun, and other sources. However, this is the likely the first time that a neutrino that has oscillated from one type into another has been directly observed. It is as if, after having learned of a crime, the victim's body has finally been found.

CERN has a nice video on the event.

(Tip a' the fedora to some old colleagues in the neutrino business.)

The Combinatorics of Syphilis

Tue, 25 May 2010 12:25:19 -0500

Jeffrey Shallit describes a neat medical probability puzzle:

The Army wants to do comprehensive blood tests for syphilis, a relatively rare disease, but each individual test is expensive. How can they test everyone more cheaply?
The idea is simple: mix the blood of $g$ individuals together, and test that. A positive outcome indicates that at least one person in the group has syphilis, and a negative outcome indicates that no person in the group has it. In the event of a positive outcome, test all the members of the group.

Now let $p$ be the probability that a randomly-chosen person has syphilis, and let $N$ be the population size. What is the optimal size for the group? Choose $g$ too small, and you end up doing lots of tests, because $N/g$ (the number of groups) is large. Choose $g$ too large, and it becomes very likely that testing the group will be positive, so you end up doing lots of tests again. Somewhere in between is the optimal choice of $g$.

The result, after a bit of algebra, is that one must choose $g$ to minimize

$$ \frac{1}{g} + 1 - (1 - p)^g. $$

(Read the original post for details.)

MBTA Releases the Magic Smoke

Thu, 29 Apr 2010 23:29:33 -0500

Gentle Readers of Boston: If you have the option, don't ride on the T tonight.

Passengers on a train that was passing through the area said a big white cloud of smoke came right at them, choking them and burning their eyes.

Etc. It seems to've been an electrical fire at Downtown Crossing around 22 o'clock, which tallies with the time the Green Line train I was on pulled into Park Street to the wailing of fire alarms. A couple hundred people, by my guesstimate, ended up milling around that corner of the Boston Common, watching the smoke billow up from the T entrance across the street and wondering what to do next. (Lots of flashing lights — maybe have a party?)

Funnily enough, the status displays at Lechmere were calling it a "power failure".

All kidding aside: even if nobody ended up seriously injured, I can only imagine the poor preparedness which this kind of incident could reveal.

Calling all Wannabe SuperReaders

Mon, 26 Apr 2010 17:06:12 -0500

So, I just got an e-mail from the ScienceBlogs.com Overlords reminding me, among other things, that our site has "SuperReaders". Each blogger in the Hive gets to pick two "enthusiastic and loyal readers" who get an extra-special account/password combination and, thus, the ability to pick entries for the "Readers' Picks" whoosywhatsit in the sidebar. (Said picks do not have to be from the blog of the blogger who selected the reader for glory.) For some reason lost in the vagaries of time, I never picked my doublet of sreaders.

If you'd like the opportunity to screw with the works, then, contact me, and I'll send your e-mail addresses along to the Powers Which Be.

EDIT TO ADD: One spot claimed!

EDITED AGAIN: Both spots now taken. That was faster than I expected.

Vertices on the Blogohedron, Brian Switek Edition

Mon, 26 Apr 2010 13:27:14 -0500

My SciBling Brian Switek has a couple nice pieces newly added to the aether. First, he's been interviewed about his forthcoming book, Written in Stone:

Writing about the history of science provides context for what we have come to understand about ancient life and reminds us that science thrives on the constant re-examination of what has already been discovered.

And, at the Smithsonian website, an essay on the interplay between evolution and atmosphere:

The trigger for this rampant gigantism was a peculiar, newly evolved characteristic of plants that drove oxygen levels to as high as 35 percent of the atmosphere during the Late Carboniferous. Lush equatorial forests produced a considerable amount of oxygen as a byproduct of photosynthesis, but that alone wasn't enough to drive atmospheric oxygen to such high levels. The cause was the chemical compound lignin, which plants use to build themselves up. Bacteria of the time were so inefficient at breaking down lignin in dead plants that they left behind a huge amount of carbon-rich plant material to become sequestered in the swamps (and eventually to transform into the rich coal deposits that gave the Carboniferous its name). Bacteria use oxygen as they break down carbon-rich material, but lignin prevented this process until bacteria evolved the ability to decompose the compound. This biological quirk caused oxygen levels to soar.
The surplus of oxygen allowed amphibians, which take in some of the gas through their skins, to breathe more efficiently and grow to larger sizes. Arthropods breathe in a different way: they possess a network of branching tubes called tracheae that connect small openings in an invertebrate's exoskeleton to its cells, and oxygen seeps through the body via this system. In an oxygen-rich atmosphere, more oxygen could be diffused through this branching network, and this opened up evolutionary pathways that allowed arthropods, too, to grow to gargantuan proportions. The fact that the oxygen would have increased the air pressure as well meant that the large flying insects of the time would have gotten more lift for each beat of their wings, allowing flying arthropods to reach sizes that are structurally impossible for their present-day relatives.

Millipedes three meters long: another remarkably creepy, yet thoroughly awesome, application of the square-cube law.

Perplexingly Plectic Pomerons

Mon, 26 Apr 2010 12:40:46 -0500

Consider the Lagrangian density

$$ \mathcal{L}[\tilde{\phi},\phi] = \tilde{\phi}\left((\partial_t + D_A(r_A - \nabla^2)\right)\phi - u\tilde{\phi}(\tilde{\phi} - \phi)\phi + \tau \tilde{\phi}^2\phi^2. $$

Particle physicists of the 1970s would recognize this as the Lagrangian for a Reggeon field theory with triple- and quadruple-Pomeron interaction vertices. In the modern literature on theoretical ecology, it encodes the behaviour of a spatially distributed predator-prey system near the predator extinction threshold.

Such is the perplexing unity of mathematical science: formula X appears in widely separated fields A and Z. Sometimes, this is a sign that a common effect is at work in the phenomena of A and those of Z; or, it could just mean that scientists couldn't think of anything new and kept doing whatever worked the first time. Wisdom lies in knowing which is the case on any particular day.

"Whosoever looketh on a woman to lust after her hath committed adultery with her already ..."

Mon, 26 Apr 2010 09:46:53 -0500

I confess myself to be something of a stern moralist in matters of attire. As the late Isaac Asimov said, many are the times I have looked down on low-cut dresses.

So, naturally, I have a few thoughts about the experiment going on today to test the hypothesis of Iranian cleric Hojatoleslam Kazem Sedighi (apparently a belief shared by others in power):

"Many women who do not dress modestly ... lead young men astray, corrupt their chastity and spread adultery in society, which (consequently) increases earthquakes," Hojatoleslam Kazem Sedighi was quoted as saying by Iranian media. Sedighi is Tehran's acting Friday prayer leader.

My first thought is the following:

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Last-Minute Talk Announcement: Geoffrey K. Pullum

Tue, 20 Apr 2010 15:11:00 -0500

Geoff Pullum, having been volcanoed in Boston, will be giving a talk at MIT fifty minutes from now:

Title: The Land of the Free and "The Elements of Style":
How False Claims about English Grammar Do Actual Harm
Host: Regina Barzilay
Host Affiliation: CSAIL
Date: 4-20-2010
Time: 4:00 PM - 5:00 PM
Location: MIT 32 G449 -- Vassar Street, Cambridge, Massachusetts.

Of course, since it's in the Stata Center, you'll have to take a slantwise ride in the Great Glass Elevator to get there.