Wednesday, December 30, 2015

Dodgers Sign Free-Agent Pitcher

This time, it's for real: we have signed –– past tense! –– free agent pitcher Scott Kazmir to a three-year contract.

Tuesday, December 29, 2015

Awesome Embroidered Temari Spheres

These embroidered temari spheres are awesome!

(Tip of the cap to Association for Women in Mathematics.)

Awesome Visual Illusion

This visual illusion is really cool!

Note: I originally referred to this illusion as an "optical illusion", but my friend Steve Van Hooser, a visual neuroscientist, has pointed out my use of the incorrect term: "I know you are a stickler for details, and as a visual neuroscientist I feel you'd want to know: say "visual illusion" rather than "optical illusion". Because the visual system produces this illusion. There are true "optical" illusions, like the illusion of water on a hot road ahead. That is an optical illusion because it is the diffraction of light that causes the illusion." (I have made this same error on several prior blog posts, which I may eventually look up and correct.)

Monday, December 28, 2015

Today's Headline: "German Man Dies After Blowing Up Condom Machine"

I think we may have a winner in our Headline-of-the-Week competition: "German Man Dies After Blowing Up Condom Machine".

Yup, that's a pretty spectacular headline.

(Tip of the cap to Kin Chan.)

Wednesday, December 23, 2015

Life Imitates Fluxx

Following these parking instructions works just like in the game Fluxx, right?

Randomized Controlled Trials of Parachute Intervention

Apparently, there are none. At minimum, the paper called Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials reported the following summary of their results in the preamble to their paper: "We were unable to identify any randomised controlled trials of parachute intervention."

The paper does have a serious undertone, however, as the authors are commenting about the limits of evidence-based medicine.

(Tip of the cap to Easter Eggs in Scientific Papers.)

Tuesday, December 22, 2015

What Happens in the LA Basin Stays in the LA Basin

So to speak.

(Anyway, I'll be home for the holiday season.)

Monday, December 21, 2015

Amusing Animal Photos

These animal photos are very amusing.

Saturday, December 19, 2015

Quantum Mosaic of John Stuart Bell

This mosaic of John Stuart Bell is very cool.

Tumblr: Math Professor Quotes

The Math Professor Quotes tumblr has just been brought to my attention.

(Tip of the cap to Association for Women in Mathematics.)

Friday, December 18, 2015

Would You Believe Zero Pitchers?

Just over a week ago, I thought we had signed one good pitcher and traded for another one, and now it seems that both deals have fallen through. Aroldis Chapman is being investigated under Major League Baseball's domestic-abuse policy, and the Dodgers found something they didn't like in Hisashi Iwakuma's physical. Our deal feel apart, and today comes the news that Iwakuma has resigned with the Mariners after all.

We've also lost Zack Greinke because we were unexpectedly stingy, so this hasn't been a particularly good offseason so far. Hopefully, the three-way trade with the Reds and White Sox will pave the way for acquiring somebody like José Fernández...

Comic Panels: "Good Mathematician vs Great Mathematician"

Here is a series of comic panels called "Good Mathematician vs Great Mathematician".

(Tip of the cap to Karen Kustedjo.)

Wednesday, December 16, 2015

"Complexity: A Story of Love and 'Power Laws'"

Apparently, somebody at Oxford is supposed to take complex systems and turn it into a work of fiction (taking inspiration from Alice in Wonderland, etc.)

Ten Thousand Years of Fresh Air

Well, life once again imitates Spaceballs: A Canadian company is important canisters of clean air to China.

The need to get fresh air from the planet Druidia is one of the central plot points of Spaceballs. Here is one of the relevant quotes: Ah, planet Druidia. And under that air shield, ten thousand years of fresh air. We must get through that air shield!

And, of course, life has imitated Spaceballs several times: This includes not only an incident of "mowing the ocean" (which is only slightly more effective than combing the desert) and the hacking of a combination that is the kind of thing an idiot would have on his luggage but also a chastity belt and canned oxygen for sale. This story revisits the canned oxygen.

Sunday, December 13, 2015

"I Don't Want to be a Pie!"

The Improbable Research Blog has passed along a pie chart that tabulates (or perhaps 'pie-bulates'?) the various causes of death in Shakespeare's plays. (Being baked into a pie would have to suck.)

Fractions of Worms and Singular Limits

Do you know what's worse than taking a bite out of an apple and finding a worm? Taking a bite of an apple and finding half a worm. And do you know what's even worse than that? Taking a bite and finding a quarter of a worm? And even worse than that is taking a bite and finding an eighth of a worm.

I can continue like this, and finding progressively smaller fractions of a worm after the delicious bite is progressively worse --- until we get to the situation in which we take a bite of an apple and don't have any worm. That's the best situation, as we have a normal delicious apple without any worm in it.* In mathematics, we refer to situations like this as a singular limit: the situation of setting a value equal to zero is qualitatively different from the situation of considering a sequence of values that we let approach zero. This is a very important concept in what is called singular perturbation theory, and it shows up all over the place in mathematics and its applications (e.g., in fluid mechanics, quantum mechanics and semiclassical limits, and many other places).

*Unless, of course, one swallows an entire worm with the bite, in which case it's a regular limit and we lose.

(Note: I don't remember seeing this analogy for singular limits before, but if somebody used it and I blocked out where I should be giving credit, please let me know. I could imagine somebody like Steve Strogatz using this type of analogy, for example, but I don't remember seeing him or anyone else use it.)

Update: Dominic Vella reminds me that Michael Berry used this analogy in an article in Physics Today. I definitely read that article, so I assume I got the analogy from there and forgot about it. I did have a nagging feeling that I must have seen it somewhere before even though I wasn't able to place it. And, no, I am not surprised that Michael Berry would use such an analogy. He's very good with analogies (and many other things).

Saturday, December 12, 2015

Jose Canseco's Plans for Terraforming Mars

José Canseco has announced his plans for terraforming Mars on Twitter.

Clearly, this is a follow-up to his theory of gravity.

I love the terse 'trending' headline on Twitter.

Thursday, December 10, 2015

Congratulations to Dr. Valentin Danchev!

The D.Phil. thesis of my student Valentin Danchev (now a postdoc in the Knowledge Lab at University of Chicago) has now been officially approved. Valentin's other supervisor was Michael Keith of COMPAS (Centre on Migration, Policy, and Society) at University of Oxford.

Valentin is a sociologist and was a D.Phil. student in University of Oxford's International Migration Institute. His thesis is called Spatial Network Structures of World Migration: Heterogeneity of Global and Local Connectivity, and we have a joint paper on the topic in progress. We plan to submit that paper to a sociology journal.

Monday, December 07, 2015

New Dodger Pitchers (or Possibly Only One New Pitcher...)

The Los Angeles Dodgers have picked up two new pitchers: we signed free-agent starter Hisashi Iwakuma to a three-year deal, and we traded a pair of prospects to the Reds for power reliever Aroldis Chapman.

I hope we can pick up another good starter. Losing Zack Greinke to the Diamondbacks left a gaping hole in our rotation.

Update (12/08/15): Then again, it may take a few weeks for the trade for Chapman to go through --- if the Dodgers bother going through with the trade at all. (And is it really a good idea to acquire somebody with this kind of personal track record?)

Update (12/18/15): It may actually end up being zero pitchers. Um, bring back Zack Greinke?

Tales from the ArXiv: Modern Art

It is usually a good idea to preview the compiled file when you upload a paper to the arXiv. (The topic of the paper looks interesting, by the way.)

Otherwise, all of your figures might be plastered over each other on the same page.

Saturday, December 05, 2015

"How Math Works": A Comic Strip About a Fundamental Truth

The new SMBC, which is titled "How Math Works", is spectacular. It also gets at a fundamental truth, and it does so in an amusing way. (It is of course exaggerated.)

Step 5: "I will never understand it. I will never believe it. As I go into death, with my final breath I spit on your theorem."

The other steps also speak the truth, and Step 4 is damn funny. Step 6 is also a familiar one.

Of course, pretty much all of science works this way. It is worth noting, however, that the notion of repeating experiments is a fundamental difference between science and pure mathematics.

The comic strip is of course exaggerated, but I do think it genuinely gets at a fundamental truth. Once a theorem is true, it is simply true; but if it changes a paradigm and people don't understand the argument, there can certainly be a lot of skepticism that can last a long time before things are accepted.

Update (12/14/15): Take a look at this post in the Improbable Research blog. It asks: "Does science really advance on funeral at a time?"

Front-Page Editorial in The New York Times

Today, The New York Times ran a front-page editorial for the first time since 1920. I'm very glad they've done this, and obviously it takes a lot for them to do this when the last one was almost 100 years ago. I hope it has an impact.

(Tip of the cap to Ernie Barreto and George Takei.)

What Research Papers Inspired Me?

I was asked to write about my favorite research papers (and why).

I answered what is perhaps a somewhat different question: What are some of the research papers that inspired me?

Here is my answer.

Friday, December 04, 2015

Math Postdoc Application Rage Thread

The title box of the math postdoc application rage thread on Reddit is all too real. My job applications were a long time ago, and I still have horrible memories of having to repeat the same damn piece of information on a form too many bloody times. In fact, I still have to do such damn things.

Design Fails

Here are some spectacular design fails.

(Tip of the cap to George Takei.)

Wednesday, December 02, 2015

Awesome Acknowledgements

The Science Easter Eggs blog illustrates a paper with a spectacular Acknowledgements section. (One of the authors also has the daycare that he currently attends listed as his affiliation.)

Tuesday, December 01, 2015

Tales from the ArXiv: Systemic Risk in a Galaxy Far, Far Away

Yes, really.

The abstract begins: In this paper we study the financial repercussions of the destruction of two fully armed andoperational moon-sized battle stations ("Death Stars") in a 4-year period and the dissolution ofthe galactic government in Star Wars.

(Tip of the cap to Guido Caldarelli.)

"Estimating Interevent Time Distributions from Finite Observation Periods in Communication Networks"

Here is the latest paper in my "please do this stuff more carefully" series.

People have been getting things wrong when it comes to examining inter-event time (IET) distributions, and there are methods from other fields (e.g., renewal processes) that allow one to correct for biases.

Here are the details of the paper.

Title: Estimating Interevent Time Distributions from Finite Observation Periods in Communication Networks

Authors: Mikko Kivelä and Mason A. Porter

Abstract: A diverse variety of processes––including recurrent disease episodes, neuron firing, and communication patterns among humans––can be described using interevent time (IET) distributions. Many such processes are ongoing, although event sequences are only available during a finite observation window. Because the observation time window is more likely to begin or end during long IETs than during short ones, the analysis of such data is susceptible to a bias induced by the finite observation period. In this paper, we illustrate how this length bias is born and how it can be corrected without assuming any particular shape for the IET distribution. To do this, we model event sequences using stationary renewal processes, and we formulate simple heuristics for determining the severity of the bias. To illustrate our results, we focus on the example of empirical communication networks, which are temporal networks that are constructed from communication events. The IET distributions of such systems guide efforts to build models of human behavior, and the variance of IETs is very important for estimating the spreading rate of information in networks of temporal interactions. We analyze several well-known data sets from the literature, and we find that the resulting bias can lead to systematic underestimates of the variance in the IET distributions and that correcting for the bias can lead to qualitatively different results for the tails of the IET distributions.

Tales from the ArXiv: Duck Dodgers and Bifurcation Diagrams

I hope that the authors of this paper make references to Duck Dodgers when they bring up this work in seminars.