Thursday, October 19, 2017

We're Going to the World Series!!!!

The Dodgers are going to the World Series for the first time since 1988!!!!!!!!

Update: The co-most valuable players (co-MVPs) of the National League Championship Series, in which we just beat the Chicago Cubs, are Chris Taylor and Justin Turner. (I thought that Justin Turner would be the lone MVP, but this choice also seems sensible.)

My Own. Personal. Polynomial.

My own. Personal. Polynomial.

Something to interpolate.
Before it’s too late.

Anyway, here is my personal polynomial.

(Tip of the cap to Dave Richeson.)

Monday, October 16, 2017

Quote of the Day: Differential Equations and Star Wars Robots

"You know you're in trouble if the different cases for your differential-equation solutions start sounding like the names of Star Wars robots."

(That is my spontaneous gem from today's lecture. We're doing Frobenius series.)

Sunday, October 15, 2017

Alternative Cuss Words

I am highly amused by this pamphlet of alternative cuss words.

Well kiss my grits!

Some of the alternatives (e.g., "cotton pickin" and some others) that are considered ok in this crib sheet are actually really bad if one thinks about them. And some of the ones to "handle with care" seem just fine to me. Also, I'm not sure what game-show hosts like Alex Trebek, Pat Sajak, and Bob Saget have to do with any of this.

(Tip of the cap to Ajay Johnson.)

Update: Steve Van Hooser pointed out "son of a motherless goat" as a particularly good one. Indeed it is, and I fondly remember its use in the show Perfect Strangers.

"The Interested Reader"

I love how many mathematics papers refer "the interested reader" to various sources for more information.

It is a little-known—but not terribly surprising—fact that most mathematics papers have only a single reader, who may or may not actually be interested in further discussion.

Saturday, October 14, 2017

An Ancient Roman Dice Tower

It would be awesome to whip out one of these — ideally, along with an ancient d20 — during a Dungeons & Dragons game.

(Tip of the cap to Sydney Padua.)

Friday, October 13, 2017

An MRI Scan of Broccoli Looks Like Fireworks


(You're welcome. Tip of the cap to Ciro Cattuto.)

Sunday, October 08, 2017

Visualizations of Music

These visualizations are really cool!

(Tip of the cap to Lucas Lacasa.

Friday, October 06, 2017

Dame Frances Kirwan Named "Savilian Professor" at University of Oxford!

Here is some really big news: "Dame Frances Kirwan has been elected to the Savilian Professorship at the University of Oxford. Frances will be the 20th holder of the Savilian Chair (founded in 1619), and is the first woman to be elected to any of the historic chairs in mathematics."

This is a very big deal. (See the Wikipedia entry for a discussion of this professorship.)

I know Frances. (We were colleagues in the Mathematical Institute at University of Oxford, of course) She is awesome (both as a mathematician and as a person).

Frances is somebody who is well-known within mathematics but pretty much unheard of outside mathematics.

Wednesday, October 04, 2017

Headline: "Massive Wave of Butterflies Lights Up Denver Weather Radar"

How very chaotic. :)

At least the radar wasn't jammed.

(Tip of the cap to Ioana Marilena.)

Tuesday, October 03, 2017

Infinite-Series Techniques: "A Good Psychological Restorative"

Yes, really—at least as prescribed by Drs. Bender and Orszag. Take two of these and call me in the morning.

Update (10/04/17): PBS is now involved (as you can see below).

Monday, October 02, 2017

RIP Tom Petty (1950–2017)

After experiencing cardiac arrest earlier this morning, and amidst conflicting reports earlier in the day, it's now been confirmed—unfortunately but unsurprisingly—that Tom Petty has died at the age of 66. (This is consistent with the recent shelf life of rockers. :( )

I got the chance to see Tom Petty and the Heartbreakers in concert for the first time just 11 days ago, and they were awesome!

You can read more about Petty from Wikipedia page. He has a lot of awesome songs, and here's a link to Learning to Fly as just one of them. Because of the music video for Don't Come Around Here No More, Petty will also always be my vision of The (Mad) Hatter. There are many other awesome songs to which I could also link.

Here is the obituary, which includes some interesting tidbits that are not in the article above.

Nobel Prize in Physiology or Medicine Awarded for Work on the Circadian Rhythm

The 2017 Nobel Prize in Physiology or Medicine was awarded for discovering molecular mechanisms that control the circadian rhythm!

Friday, September 29, 2017

The Importance of Specifying Units

It is extremely important to specify units. :)

Also: very well-played!

(Tip of the cap to Melvin Leok.)

Thursday, September 28, 2017

New Technology: Playable Records Made from Oreo Cookies

I know this sounds nuts, but I'm serious! And I from a physics perspective, this seems eminently doable.

I know of a great song that would be perfect to turn this into a Caltech-themed prank...

Given these developments, we clearly need a DJ Cookie Monster to take proper advantage of this new technology.

Pictures from Puebla

Here is my photo album from Puebla.

Some of the pictures from the archaeological site are especially cool!

Sunday, September 24, 2017

What Happens in Puebla Stays in Puebla

Today I am flying to Puebla, Mexico to attend LANET 2017, the 1st Latin American Conference on Complex Networks.

As you probably know, there was an earthquake there a few days ago, but the conference is still happening (and only a few people have cancelled). The show must go on!

Friday, September 22, 2017

The Dodgers Win the National League West

The Dodgers just beat the Giants 4–2 and are now National League West champions for the 5th year in a row. Today's win was our 98th of the year.

The inevitable celebration got delayed quite a while by our horrible slump, but we did it—and on Tommy Lasorda's 90th birthday to boot!

Next stop: the National League Division Series on Friday 6 October at Dodger Stadium.

What Programmers Say When Their Software Doesn't Work: Top 20 Responses

I have witnessed several of these and used some others.

(Tip of the cap to Michael Stumpf.)

Sunday, September 17, 2017

Words Well Hung

I can see myself uttering last words along these lines (though I can do without the hanging).

(Tip of the cap to George Takei.)

Contribute to Science with your Dungeons & Dragons Backstories

Yes, really.

(Tip of the cap to Jennifer Ouellette.)

The Origin of Zork

Here is a short article about the origin of the landmark text-adventure computer game Zork.

We should calculate some network statistics of the Great Underground Empire map. (See the salient hand-drawn figure in the article.)

Saturday, September 16, 2017

But Can We Set the Lyapunov Exponent?

Apparently, there is a microwave with a 'CHAOS' mode (in all caps).

I have only one question: Are we allowed to set the Lyapunov exponent? (Technically, I am thinking of the maximum one.)

(Tip of the cap to George Takei.)

Update: It looks like chaotic dynamics actually are explicitly involved. (Tip of the cap to Melvin Leok for the link.)

Update 2: Following up on Melvin's comment, I did some googling and found this article. I still haven't figured out which system they used. I suppose I should treat this like the chaotic water wheels. The people who designed this option could have chosen any one of the standard models.

Update 3: Bah. The relevant reference is in a conference proceeding whose parent domain is dead (probably long dead). I might actually have to use a physical library to determine decisively which system was used. (Jaroslav Stark, one of the authors of the above perspective piece, died several years ago. I could potentially see if his coauthor, who I have never heard of, is reachable. The names of the authors of that conference proceeding are going to defy Google.)

Wednesday, September 13, 2017

New to the Blogroll: Math with Bad Drawings

On occasion, I have really enjoyed entries from the blog Math with Bad Drawings, and I am now adding it to the blogroll (much later than I should have).

Great Opening Lines from Literature as Written by Mathematicians

I approve of this blog entry!.

(Tip of the cap to MathFeed.)

21-Game Winning Streak!

This year's Cleveland Indians now are alone at the top with an American League record 21-game winning streak that matches the 1935 Chicago Cubs for the second-longest streak since 1900. The Major League record is 26 non-losing games (it included a tie) by the 1916 New York Giants.


Update (9/15/17): The Indians lost today to the Royals. They won yesterday, so their win streak reached 22 games. Wow!

Tuesday, September 12, 2017

The Bee Nailed It

(I saw this Tweet because Sabine Hossenfelder liked it.)

Monday, September 11, 2017

"Lock the Taskbar"

Does he think it's not kosher?

(Tip of the cap to Dave Richeson.)

Thursday, September 07, 2017

Last Will and Temperament

I haven't seen this picture in several years.

I humbly request that, when I am gone, many of these (but with my name, instead of this guy's) be made and installed at appropriate spots all over the world. I may have to put this as a condition in my will.

Also, I want my sign to be grammatically correct.

P.S. The title is an allusion to this skit.

(Tip of the cap to Gabor Vattay.

Wednesday, September 06, 2017

"Nonlinear Coherent Structures in Granular Crystals"

My review article on granular crystals (and especially work on it during the last decade) just came out in final form. Here are the details.

Title: Nonlinear Coherent Structures in Granular Crystals

Authors: Chris Chong, Mason A. Porter, Panayotis G. Kevrekidis, and Chiara Daraio

Abstract: The study of granular crystals, which are nonlinear metamaterials that consist of closely packed arrays of particles that interact elastically, is a vibrant area of research that combines ideas from disciplines such as materials science, nonlinear dynamics, and condensed-matter physics. Granular crystals exploit geometrical nonlinearities in their constitutive microstructure to produce properties (such as tunability and energy localization) that are not conventional to engineering materials and linear devices. In this topical review, we focus on recent experimental, computational, and theoretical results on nonlinear coherent structures in granular crystals. Such structures—which include traveling solitary waves, dispersive shock waves, and discrete breathers—have fascinating dynamics, including a diversity of both transient features and robust, long-lived patterns that emerge from broad classes of initial data. In our review, we primarily discuss phenomena in one-dimensional crystals, as most research to date has focused on such scenarios, but we also present some extensions to two-dimensional settings. Throughout the review, we highlight open problems and discuss a variety of potential
engineering applications that arise from the rich dynamic response of granular crystals.

Tuesday, September 05, 2017

Sunday, September 03, 2017

Complex Analysis, Simple Analysis, and Congressional Support for Perverse Sheaves

This quote encapsulates one of the great stories in the history of U.S. government funding (and legislative and others' skepticism of such funding):

"On April 9, 1975, Congressman Robert Michel brandished a list of new NSF grants on the floor of the House of Representatives and selected a few that he thought might represent a waste of the taxpayers’ money. One of them (on which I happened to be one of the investigators) was called “Studies in Complex Analysis.” Michel’s comment was, “ ‘Simple Analysis’ would, hopefully, be cheaper.” I shudder to think of what might happen if certain members of the current Congress discover that the NSF is supporting research on perverse sheaves."

You can see some more details in an old blog post from John Baez.

Happiness is Not Communicating :)

Note that, on average, the happier people spend much less time communicating with other people electronically. (For example, notice the result for "Phone".)

I take that a step further and try not to spend too much time communicating with others (electronically or otherwise), and I am extremely happy!

(Tip of the cap to Hiroki Sayama.)

Saturday, September 02, 2017

"Bullshit and the Art of Crap Detection" (1969 Speech)

Take a look at this speech by Neil Postman from 1969. It is called "Bullshit and the Art of Crap Detection".

I had heard of this before, and I found it today through the Twitter post below, where again note that it was uttered in 1969.

Friday, September 01, 2017

The Masque of the Chaotic Attractor

(This could, however, work very well at Dynamics Days.)

Thursday, August 31, 2017

"Everything Sounds Better with Mathematics"

As the blog Math with Bad Drawings points out, everything sounds better with mathematics.

Damn right!

For example, cavities are "just point discontinuities of oral hygiene!"

Wednesday, August 30, 2017

Fake µs

I am very amused by the title ("Fake μs: A cautionary tail of shear-thinning locomotion") of this paper.

It's too bad, though, that "µ" is the standard notation for kinematic viscosity, as the title would be even more amusing with the notation "𝜈" for dynamic viscosity. It would then be "Fake 𝜈s". In any event, I approve! (And things are open for a sequel paper about dynamic viscosity.)

Also, I like viscous puns.

I previously used a variant of this pun, as you can see below.

Update (8/31/17): Thanks to Peter Mucha for the comments about kinematic versus dynamic viscosity. This helped me improve my comments above.

"Skype a Scientist" Program

I just received a classroom 'match' through the Skype a Scientist. My match is a 9th-grade classroom, but the range is kindergarten through 12th gradel.

Fellow scientists: You should sign up for this! It's a really good cause!

"Skype a Scientist matches scientists with classrooms around the world! Scientists will skype into the classroom for 30-60 minute Q and A sessions that can cover the scientist’s expertise or what it’s like to be a scientist. We want to give students the opportunity to get to know a “real scientist”, and this program allows us to reach students from all over the world without having to leave the lab!"

Update (9/06/17): I now have been matched with a second classroom. I believe I indicated that I was happy being matched with up to two classrooms.

Sunday, August 27, 2017

Another Cool Visual Illusion

(Tip of the cap to Justin Lanier.)

Saturday, August 26, 2017

Will Love Tear this Research Apart?

Yes, the actual reason that this type of visualization is now called a "joyplot" is because of the classical Joy Division cover. Sometimes things are right in the world.

Even if love doesn't tear their paper apart, the referees surely will.

I also wrote about this here and here.

(Tip of the cap to MathFeed.)

Update (8/27/17): You can also see some discussion of this visualization in my Facebook post.

Friday, August 25, 2017

Popsicle-Stick "Cobra Wave"

This is cool! Here is an explanation.

We got the video from PRL's tweet.

Thursday, August 24, 2017

Quote of the Day: Moscow Student Sex Survey from 1903

This quote speaks for itself.

(Tip of the cap to Craig Montuori.)

Wednesday, August 23, 2017

28th Anniversary of Ejection from a Game of Expos' Mascot

28 years ago today, The Expos' mascot (Youppi!) got ejected from a game against the Dodgers, partly at the urging of Dodger manager Tommy Lasorda.

The antics that the Phillie Phanatic would pull with Tommy Lasorda were even funnier.

Monday, August 21, 2017

"Subtitles: What the Book is Actually About"

Just for the irony, I'd like to write a book called "Subtitles: What the Book is Actually About". :)

Wednesday, August 16, 2017

Eclipses Go Meta

Good. Something is right in the world. (Also, I strongly approve of this!)

(Tip of the cap to several people for this news. I got the tweet from Cathy O'Neil.)

Monday, August 14, 2017

What Happens in Edmonton Stays in Edmonton

Today I'm off to Edmonton — home of the Eulers!

I will be giving an invited talk at a (mostly) pure-math conference on differential equations.

Sunday, August 13, 2017

A Sweet Early Calculator!

Very cool!

(Tip of the cap to Daniele Avitabile.)

Saturday, August 12, 2017

Differential Equations and "General Fiction"

Eugenia Cheng's tweet below reminds me that when I was in grad school, a local store (a coffee place that also sold books) once had a certain differential-equations textbook in their section on "General Fiction".

Thursday, August 10, 2017

A Tetris-Themed Glass Window (and Other Nerd Furniture)

Take a look at this sweet nerd furniture!

Update (8/11/17): Initially I described the Tetris window as a "stained-glass window". As Aaron Clements pointed out on my Facebook post, a correct description is actually "colored glass blocks with mortar".

(Tip of the cap to Rachel Simmons Carter.)

Another Optical Illusion: How Many Circles Can You Find?

Here's another optical illusion. It's not as visually striking as the other one I posted recently, but it's interesting (and, unlike the other one, the basic qualitative feature of the illusion is not one that I have not encountered before).

Wednesday, August 09, 2017

"Core-Periphery Structure in Networks (Revisited)"

One of my papers just came out in published form. In fact, it's a SIAM Review reboot (with some new sections and other updates) of our paper from a few years ago. Here are the details.

Title: Core-Periphery Structure in Networks (Revisited)

Authors: Puck Rombach, Mason A. Porter, James H. Fowler, and Peter J. Mucha

Abstract: Intermediate-scale (or “meso-scale”) structures in networks have received considerable attention, as the algorithmic detection of such structures makes it possible to discover network features that are not apparent either at the local scale of nodes and edges or at the global scale of summary statistics. Numerous types of meso-scale structures can occur in networks, but investigations of such features have focused predominantly on the identification and study of community structure. In this paper, we develop a new method to investigate the meso-scale feature known as
core-periphery structure, which entails identifying densely connected core nodes and sparsely connected peripheral nodes. In contrast to communities, the nodes in a core are also reasonably well-connected to those in a network’s periphery. Our new method of computing core-periphery structure can identify multiple cores in a network and takes into account different possible core structures. We illustrate the differences between our method and several existing methods for identifying which nodes belong to a core, and we use our technique to examine core-periphery structure in examples of friendship, collaboration, transportation, and voting networks. For this new SIGEST version of our paper, we also discuss our work’s relevance in the context of recent developments in the study of core-periphery structure.

"A Roadmap for the Computation of Persistent Homology"

One of my papers just came out in published form. Here are the details.

Title: A Roadmap for the Computation of Persistent Homology

Authors: Nina Otter, Mason A. Porter, Ulrike Tillmann, Peter Grindrod, and Heather A. Harrington

Abstract: Persistent homology (PH) is a method used in topological data analysis (TDA) to study qualitative features of data that persist across multiple scales. It is robust to perturbations of input data, independent of dimensions and coordinates, and provides a compact representation of the qualitative features of the input. The computation of PH is an open area with numerous important and fascinating challenges. The field of PH computation is evolving rapidly, and new algorithms and software implementations are being updated and released at a rapid pace. The purposes of our article are to (1) introduce theory and computational methods for PH to a broad range of computational scientists and (2) provide benchmarks of state-of-the-art implementations for the computation of PH. We give a friendly introduction to PH, navigate the pipeline for the computation of PH with an eye towards applications, and use a range of synthetic and real-world data sets to evaluate currently available open-source implementations for the computation of PH. Based on our benchmarking, we indicate which algorithms and implementations are best suited to different types of data sets. In an accompanying tutorial, we provide guidelines for the computation of PH. We make publicly available all scripts that we wrote for the tutorial, and we make available the processed version of the data sets used in the benchmarking.

Tuesday, August 08, 2017

"Opposite" Jobs

According to this website, the "opposite" job of a kindergarten teacher is a physicist, whose opposite job is a model (so it's a directed similarity measure, as it should be, so really one should write "most different" rather than "opposite" to encapsulate the directionality).

According to this, the most different job from "mathematician" is "mine shuttle car operator".



I am highly amused by this classification. :)


My collaborator Sam Howison brought up Cassandra in our skype meeting today. Apropos to current reality, "Cassandra is a prophetess in Greek mythology who was blessed with foresight but cursed never to be believed."

Naturally, the first thing that came to my mind that Sam mentioned Cassandra was not the prophet, but rather the ABBA song (which turns out to be a B-side). And checking the lyrics, the song does indeed refer to the prophet.

Monday, August 07, 2017

Awesome Optical Illusion: Bathroom Tile Edition

Versions of this optical illusion (much less elaborate variants of it) appear to be ubiquitous in restaurant bathroom tiles. :)

Saturday, August 05, 2017

Dodgers Have Best 50-Game Run Since 1912!

With their come-from-behind win today, the Dodgers are now 43–7 in their last 50 games, the best 50-game run since the 1912 Giants! Wow!

Friday, August 04, 2017

A Multiplex Network of Relations Between Probability Distributions

OK, quickly: Which distribution is the most central? :)

(There are quite a few comments on the tweet. I haven't looked at them, but I wonder if people are picking apart inaccuracies? I haven't spent the time to vet this diagram, but I really like the idea!)

A Classic Article: "More is Different"

Now that it's officially August 4th, today marks the 45th anniversary of Philip Anderson's famous article, More is Different, a landmark article for the study of complex systems. Here is a link to the full article, in case you don't have access to Science articles.

(Tip of the cap to Michael Stumpf.)

Thursday, August 03, 2017

What is the Weirdest Historical/Superstitious Practice in Academia?

This is definitely it.

I saw this yesterday, but I didn't post it because the embedded tweet wasn't showing the original question. I should have taken a screenshot and posted it. :)

Tuesday, August 01, 2017

Mathematicians and Physicists on Twitter

Here is a list of mathematicians on Twitter with 1000+ followers. However, they missed me. I would rank number 70, assuming they didn't miss anybody with more followers than me.

Here is a list of physicists on Twitter with 1000+ followers. I am not on this list either, though it can be argued that I am also a physicist (in addition to being a mathematician).

Update (8/03/17): My account is now on the list of mathematicians.

Monday, July 31, 2017

Dodgers Get Yu Darvish (and Two Left-Handed Relievers)!

The Dodgers made a huge trade today: we acquired starting pitcher Yu Darvish from the Texas Rangers for three prospects.

In separate deals, we also traded for left-handed relief pitchers Tony Watson of the Pirates and Tony Cingrani of the Reds.

Sunday, July 30, 2017

Dodgers Win (Again)!

Dodgers win!

This team is so amazing.

We now have an astounding 74–31 record (after our 8th win in a row, and recently we had 10-game and 11-game winning streaks).

We also now have a 14-game lead!

Adrián Beltré Gets 3000th Career Hit!

Adrián Beltré just got his 3000th career Major League hit.

Next stop, Cooperstown! And it will be on the first ballot.

Beltré has been appreciated more in recent years as his counting numbers approach 'magic' milestones, but I still don't think most people truly appreciate just how excellent his career has been. I can't remember who wrote this — was it — but I recently saw an estimate that put him in the top-5 third basemen of all time.

There is also a discussion at about future members of the 3000-hit club. The next member will be Albert Pujols, who will become the second person from the Dominican Republic (Beltré is the first) in the 3000-hit club. I believe that the next person after that will be Miguel Cabrera and then Robinson Canó. (Here are the active leaders in career hits.)

Update: Here's a new article in about Beltré's greatness as both an offensive player and defensive player.

Saturday, July 29, 2017

Super Geniuses :)

(Tip of the cap to Melanie Mitchell.)

Friday, July 28, 2017

Amazing Street Art

This street art is amazing!

(Tip of the cap to multiple people.)

Things Rick Astley Would Never Do: 30-Year Anniversary

I wore my 'Things Rick Astley Would Never Do' shirt two days ago, but had I known that the song was released 30 years ago yesterday, I would have instead worn the shirt yesterday to celebrate in a proper manner.

Thursday, July 27, 2017

The Proper Way to Record 'A-Ha' Moments

We've spent a lot of time this week talking about A-Ha moments for students, and now I know the app that I'm going to use to record them!

(I don't normally care about gratuitous apps, but I am seriously geeking out over this one! I want to try this out.)

P.S. The video for "Take on Me" is the best music video of all time! And this is one of the best songs all time — definitely in my top 5.

Mathematican–Footballer John Urschel Retires Abruptly

Mathematical and National Football League (NFL) player John Urschel has retired abruptly after the release of the latest chronic traumatic encephalopathy (CTE) study.

It's too bad that he won't continue pursuing both careers, but I have to say that I feel warm and fuzzy about passion for mathematics being such an important facet of his decision. (And his publication record for somebody at his career stage is very impressive even before considering the fact that he's simultaneously been playing pro football, which then makes it astounding.)

"I think it hurt my ability to think well mathematically," Urschel said. "It took me about three weeks before I was football-ready. It took me a little bit longer before my high-level visualizations ability came back."

(Tip of the cap to Eric Eager.

Sunday, July 23, 2017

Highlighting Responses to Reviewers


A 1995 Dystopian Vision of the Web

This article, presenting a dystopian vision of the Web, was written by astronomer Clifford Stoll in 1995. A recent article discusses Stoll's 1995 piece.

(Tip of the cap to Manlio De Domenico, who retweeted Valids Krebs.)

Friday, July 21, 2017

Math Profs are the Least Boring (And Other Observations from Data Analysis)

Here is some interesting data analysis using reviews from Rate My Professors.

You can see from this data analysis that math professors appear to be the least boring among all professors (yay!) and there are some expected (and perhaps more surprising) gender gaps (boo!) in the reviews.

(Tip of the cap to Nicholas Christakis.)

Wednesday, July 19, 2017

'National Nobody Cares Day'

April 11th is `National Nobody Cares Day'. Yes, this really exists.

(The things I learn when listening to a baseball game... The context, unsurprisingly, is all of the rather specific days there are — several of them each day — and most of them seem rather pointless. For example, tomorrow is National Lollypop Day.)

Wow! The Dodgers are Insane!

We're leading 9–1 today in the 6th inning, so presumably we will win.

That will make 11 wins in a row and a 31–4 record in our last 35 games!

Entering today, with our record of 65–29, we were more games above .500 than we have been any day since the last day of the 1974 season (so before I was born), when we won 102 games.


Also, based on current records (or perhaps All-Star break records?), 30 out of our first 36 games after the break are slated to be against teams that are under .500.

"The Tonight Show" Starring Edward Teller?

Wow. Here are some pictures of Edward Teller as a television-show host.

Tuesday, July 18, 2017

Turkey Tail Mushrooms

Wow! These turkey tail 'shrooms are beautiful!

(Tip of the cap to GrrlScientist.

Monday, July 17, 2017

Not "Atomic Blondie"

I saw a billboard for the movie Atomic Blonde from my apartment building, and I was really excited that there was going to be a biopic about the band Blondie. So I looked up the IMDB entry, and the movie is in fact rather different.

This, by the way, was a very natural mistake to make. I hope that the song "Atomic" is in the film, at least.

Sunday, July 16, 2017

Bansky's Tweet about Modern-Day Education

The cartoon below illustrates the point very effectively.

Just about* every time that I got into trouble at school was an instance of rebelling against this (which was already the case when I was in elementary school and high school).

* Most other instances involved a radio and a baseball game.

(Tip of the cap to Nalini Joshi.)

Saturday, July 15, 2017

RIP Maryam Mirzakhani (1977–2017)

Another person has been taken from us way too soon, and this one is particularly sad. Mathematician Maryam Mirzakhani, the only woman to ever win the Fields Medal (though I look forward to changing that description to "the first" rather than "the only"), has died of cancer at age 40.

Here is the BBC's obituary.

(Tip of the cap to Nalini Joshi.)

Update: The Stanford obituary was written nicely. (Tip of the cap to Leslie Sheppard.)

Update: Here is Terry Tao's tribute.

Update (7/18/17): Here is the AMS's brief obituary, which includes links to some other tributes as well as prior articles.

Update (8/15/17): Here is a blog entry by Anna Haensch with links to various articles about Mirzakhani and other prominent women mathematicians who died recently.

Friday, July 14, 2017

Do the Laws of Australia Supercede the Laws of Mathematics

Australian Prime Minister Malcolm Turnbull apparently thinks so. To quote him, "Well the laws of Australia prevail in Australia, I can assure you of that. The laws of mathematics are very commendable, but the only law that applies in Australia is the law of Australia."

Good luck with that one.

Thursday, July 13, 2017

Uncountably Many Espresso Combinations

The new SMBC is about both mathematics and coffee, so it's right up my alley.

I'm pretty sure that one can also use a modification of the "diagonal argument" to prove that the set is uncountable. :)

Wednesday, July 12, 2017

Tuesday, July 11, 2017

What Happens in Pittsburgh Remains in Pittsburgh

I am heading off to the 2017 SIAM Network Science Workshop, which I am co-organizing with Michelle Girvan. I'll also be making occasional cameos at the SIAM Annual Meeting. On Friday night, I'll go to the local baseball game to see the Pirates host the Cardinals.

Monday, July 10, 2017

What Happens in Nottingham Stays in Nottingham

I am off to Nottingham for today and part of tomorrow for a collaboration meeting about piecewise-smooth systems.

Sunday, July 09, 2017

7.5-Game Lead!

With today's Dodger victory, coupled with a loss by the Diamondbacks, the Dodgers have extended their lead in the National League West to 7.5 games. We are now 61–29, which is the best record in Baseball! (Yesterday we narrowly went ahead of the Astros.) If we play .500 baseball the rest of the year, we'll end up with 97 wins, which is the most that the Dodgers have had in the regular season since 1977. Very cool!

Wednesday, July 05, 2017

"Mean-Field Approach to Evolving Spatial Networks, with an Application to Osteocyte Network Formation"

One of my papers came out in final form today. Here are the details.

Title: Mean-Field Approach to Evolving Spatial Networks, with an Application to Osteocyte Network Formation

Authors: Jake P. Taylor-King, David Basanta, S. Jonathan Chapman, and Mason A. Porter

Abstract: We consider evolving networks in which each node can have various associated properties (a state) in addition to those that arise from network structure. For example, each node can have a spatial location and a velocity, or it can have some more abstract internal property that describes something like a social trait. Edges between nodes are created and destroyed, and new nodes enter the system.We introduce a "local state degree distribution" (LSDD) as the degree distribution at a particular point in state space. We then make a mean-field assumption and thereby derive an integro-partial differential equation that is satisfied by the LSDD. We perform numerical experiments and find good agreement between solutions of the integro-differential equation and the LSDD from stochastic simulations of the full model. To illustrate our theory, we apply it to a simple model for osteocyte network formation within bones, with a view to understanding changes that may take place during cancer. Our results suggest that increased rates of differentiation lead to higher densities of osteocytes, but with a smaller number of dendrites. To help provide biological context, we also include an introduction to osteocytes, the formation of osteocyte networks, and the role of osteocytes in bone metastasis.

Tuesday, July 04, 2017

Best. Erratum. Ever.

I love it! :)

Sunday, July 02, 2017

What Happens in Newcastle Stays in Newcastle

I just spent much of the weekend in Newcastle hanging out with old friends.

A Wikipedian Text Adventure

Someone wrote some software to turn Wikipedia into a text adventure in a really nice homage to Infocom. I approve!

Tuesday, June 27, 2017

What Happens in London Stays in London

I'll be in London for a couple of days for a meeting with one of my industrial collaborators and the Royal Society Workshop on Mathematics for the Modern Economy. Come to the workshop!

Spaceballs: The Anniversary

Saturday 24 June marked the 30th anniversary of Spaceballs, one of the best movies of all time.

Monday, June 26, 2017

Historical Naval Charts and Maps

The National Maritime Museum (one of the Royal Museums of Greenwich) has a really cool collection of historical sea charts and maps. It would be really cool to do some research involving them!

I found this out via the follow tweet.

(Tip of the cap to Sydney Padua.)

Sunday, June 25, 2017

A Really Nice Dragonfly

Check out the awesome patterns on this dragonfly!

(Tip of the cap to Meghan Duffy.)

Friday, June 23, 2017

Comic Strip: It's All Euclid's Fault

I like today's SMBC comic strip, which is about angles (and non-Euclidean geometry).

I especially like the last panel.

What Happens in Oxford Stays in Oxford

I arrived in Oxford on Wednesday for my yearly visit this year. (I plan visits for the next couple of years as well.) I'll be giving a talk tomorrow at the Somerville Maths Reunion and will also be going to the Principal's Farewell Gaudy (which covers matriculation years "after"—which perhaps actually means "since"?—2007). Several of my former Somerville undergrads will be at the math reunion, and a significantly larger number of them will be at the gaudy, so I'll get to see lots of my former students tomorrow! Sweet!

While I am based in Oxford for a bit, I'll spend a couple days in London as part of the Mathematics for the Modern Economy workshop (where I will also be giving a talk), will spend a weekend visiting friends in Newcastle, and will head to Nottingham for a day for a collaboration that is just starting up.

Tuesday, June 20, 2017

"Modeling the Lowest-Cost Splitting of a Herd of Cows by Optimizing a Cost Function"

I have a new paper out in final form today. This one took quite a lot of effort to write and to polish the exposition.

Title: Modeling the Lowest-Cost Splitting of a Herd of Cows by Optimizing a Cost Function

Authors: Kelum Gajamannage, Erik M. Bollt, Mason A. Porter, and Marian S. Dawkins

Abstract: Animals live in groups to defend against predation and to obtain food. However, for some animals—especially ones that spend long periods of time feeding—there are costs if a group chooses to move on before their nutritional needs are satisfied. If the conflict between feeding and keeping up with a group becomes too large, it may be advantageous for some groups of animals to split into subgroups with similar nutritional needs. We model the costs and benefits of splitting in a herd of cows using a cost function that quantifies individual variation in hunger, desire to lie down, and predation risk. We model the costs associated with hunger and lying desire as the standard deviations of individuals within a group, and we model predation risk as an inverse exponential function of the group size. We minimize the cost function over all plausible groups that can arise from a given herd and study the dynamics of group splitting. We examine how the cow dynamics and cost function depend on the parameters in the model and consider two biologically-motivated examples: (1) group switching and group fission in a herd of relatively homogeneous cows, and (2) a herd with an equal number of adult males (larger animals) and adult females (smaller animals).

Chaos, the journal in which we published our paper, decided to write a press release. Thus far, our work has been covered by Wired.

Congratulations to Hall Daily on his Retirement!

Hall Daily, Caltech's Director for Government Relations, is retiring after a long tenure on the job.

Back in my undergrad era, Hall Daily was also the advisor for The California Tech (our student newspaper), of which I was a writer and co-editor. I learned a ton about journalism from Hall. He too someone who was someone who Autumn Looijen and I purposely earmarked as getting one of our free copies of Legends of Caltech III. He was an awesome advisor, and I owe a lot to him for my communication and journalistic skills. My experience with The Tech was probably more important for my career than any math or science class I ever took.

Friday, June 16, 2017

How Do People from Different Cultures Draw Circles?

Here is a really interesting article about how people from different cultures draw circles.

I was once — well, at least once — told in elementary school that I was drawing circles the wrong way (because I was using the wrong sense around the clock). I think I responded with the definition of a circle and that the definition doesn't depend on the sense in which one draws it, and I think my teacher did not appreciate that.

On a similar note, in high school, I once lost 50% of the point total on an answer for misspelling ellipse (by using one 'l' instead of two), which was the correct answer. I called bullshit (on the grounds that it was my mathematics knowledge that was being tested), but unfortunately I lost.

More closely related to the article, one thing I noticed in the UK is that the most common way to write an 'x' there is with two arcs, so that they won't always cross if one writes quickly. In contrast, I write two attempts at lines that explicitly cross. (I haven't checked if this is US versus UK convention.)

And, indeed, most Americans drew their circles counterclockwise in this data set, and I draw mine clockwise.

(Tip of the cap to Improbable Research for their Facebook post.)

Update: Here is a lovely quote from the article: In a 1977 paper Theodore Blau, then-president of the American Psychological Association and creator of the torque test, argued that drawing clockwise circles was a sign of learning and behavioral aberrance.

Thursday, June 15, 2017

Participating in Commencement Ceremonies: Be Prepared

When participating in a commencement ceremony, it is important to come prepared.

During the Faculty Recession of the commencement ceremony, as professors started marching off the stage, the organist started things off with the theme to Star Wars.

I contend, however, that the Imperial March would have been far more appropriate.

Network Structure of "Choose Your Own Adventure" Novels

Network structure is very important for 'choose your own adventure' books. (My strategy was to do an exhaustive search, noting any infinite-length walks.) If you don't believe me, you can see for yourself.

Cycles FTW!

Wednesday, June 14, 2017

Discussing Mathematics in Line

Apparently, at least one deli explicitly disallows this. That's odd. (Now I want to go there, just so I can do it.)

Monday, June 12, 2017

Print and Play Cards: Women in Science

These print-and-play cards of Women in Science include some nice artwork and some very familiar names. My favorites are the mathematicians, of course.

A couple of years ago, I blogged about playing cards of Women in Computing.

"A Local Perspective on Community Structure in Multilayer Networks"

One of my papers, which came out a few months ago, final got its final coordinates (page numbers, etc.). Here are the details.

Title: A Local Perspective on Community Structure in Multilayer Networks

Authors: Lucas G. S. Jeub, Michael W. Mahoney, Peter J. Mucha, and Mason A. Porter

Abstract: The analysis of multilayer networks is among the most active areas of network science, and there are several methods to detect dense “communities” of nodes in multilayer networks. One way to define a community is as a set of nodes that trap a diffusion-like dynamical process (usually a random walk) for a long time. In this view, communities are sets of nodes that create bottlenecks to the spreading of a dynamical process on a network. We analyze the local behavior of different random walks on multiplex networks (which are multilayer networks in which different layers correspond to different types of edges) and show that they have very different bottlenecks, which correspond to rather different notions of what it means for a set of nodes to be a good community. This has direct implications for the behavior of community-detection methods that are based on these random walks.

Thursday, June 08, 2017

Quora Question: What Powers are Ph.D. Students Awarded?

I had something to say about this question.

(My Ph.D. students get awesome powers, of course! What kind of advisor do you think I am?)

Saturday, June 03, 2017

Epic-Level "Doodling" (Sometimes in 3D)

This art is amazing! The website Bored Panda described it as "doodling", though it is awesome, epic-level art (whatever you want to call it).

A Useful Website for Lingo and Grammar

This site is great! (I just found it by googling a specific example for one of my three current paper proofs.) It returns a quick set of numbers for how often different word choices are used in practice.

From the website, I see that "foundational to" is just over twice as common as "foundational for".

Subway Maps Compared to their Actual Geographies

Here are some cool visualizations of subway maps morphing to their actual geographies.

And if you want to learn about the amount of information to navigate such things, you may be interested in this paper.

(Tip of the cap to Marta González.)

Tuesday, May 30, 2017

"Survival Bread" and Other Heavily-Pinned Food Items

The most pinned food item (using Pinterest) in Alaska is called "survival bread".

There are several other amusing ones, as you can see in this map.

(Tip of the cap to George Takei.)

Monday, May 29, 2017

"Skype a Scientist": Matching Scientists with School Classrooms

I signed up to talk to a couple of classrooms via the Skype a Scientist initiative. Maybe you will too?

(Tip of the cap to Noelle Beckman.)

Ten of the Most Parodied Artworks of All Time

There are some very familiar pieces among the most parodied works of art.

Some of the parodies are rather familiar as well.

(Tip of the cap to Yves van Gennip.)

Sunday, May 28, 2017

Classic Article: "Pac-Man Bites the Dust!"

Here is a classic article from 1982 called "Pac-Man Bites the Dust!". I still probably have a hard copy of it somewhere in my parents' home. Thankfully, I was able to google it successfully.

I hadn't noticed the author's infamous "name" until today. Also, Ms. Pac-Man seems to alternate during the article between being Pac-Man's girlfriend and being his wife. I didn't remember that part either.

Mobile Phone = Cursed Pet Rock?

I agree with this tweet.

(Tip of the cap to Sean Carroll.

Friday, May 26, 2017

Data Analysis of Gender in Film Dialog

The data set used in this analysis would be really cool to explore (perhaps in combination with movie networks).

Friday, May 19, 2017

The Onion Wins Again: Roger Ailes Edition

The Onion wins yet again! This one is really funny.

An Excellent Straw Man

This SMBC is awesome! I am highly amused.

This may be my favorite ever straw man.

Blessing Computers with Holy Water

On Facebook, Jean Bellissard shared the following rather amusing article. Besides laughing, an immediate thing to do was to do a Google search and see if this was fake. That led me to this article, which notes among other things that a picture being circulated widely now is from 2013. However, the following quote also appears in the article:

"Apparently, it’s a common practice in Russia for Orthodox priests to bless server rooms and other technology equipment. So, it won’t be wrong to assume that priests might be really called in upcoming days to bless the computers once again. I just hope that priests would be careful enough to not get the water inside the PCs; I’m sure that computer suppliers won’t be enthusiastic to replace damage due to water."

I am amused.

Also, our printers could use some holy water.

Wednesday, May 17, 2017

Map of Literature's Epic American Road Trips

This visualization of epic American road trips from literature is very cool!

You have walks on networks, you have different ones that you can compare to each other, and you also have descriptions from the authors of these different places.

(Tip of the cap to Bonnie Harland.)

A Big Pile of ... Linear Algebra

That's right. In many cases, machine learning is a big pile of ... linear algebra.

Tuesday, May 16, 2017

Clever Displays in Bookstores

Like this one.

(Tip of the cap to James Gleick.)

"Quasi-Centralized Limit Order Books"

One of my papers got assigned its final journal coordinates today. (It came out a few months ago in advanced access.) Here are the details.

Title: Quasi-Centralized Limit Order Books

Authors: Martin D. Gould, Mason A. Porter, and Sam D. Howison

Abstract: A quasi-centralized limit order book (QCLOB) is a limit order book (LOB) in which financial institutions can only access the trading opportunities offered by counterpartieswithwhomthey possess sufficient bilateral credit. In this paper, we perform an empirical analysis of a recent, high-quality data set from a large electronic trading platform that utilizes QCLOBs to facilitate trade. We argue that the quote-relative framework often used to study other LOBs is not a sensible reference frame for QCLOBs, so we instead introduce an alternative, trade-relative framework, which we use to study the statistical properties of order flow and LOB state in our data. We also uncover an empirical universality: although the distributions that describe order flow and LOB state vary considerably across days, a simple, linear rescaling causes them to collapse onto a single curve. Motivated by this finding, we propose a semi-parametric model of order flow and LOB state for a single trading day. Our model provides similar performance to that of parametric curve-fitting techniques but is simpler to compute and faster to implement.

Why I Joined the American Physical Society

The American Physical Society (APS) e-mailed its 2016 Fellows to ask them to write a sentence or two about why they joined the APS.

They wrote: "If you can tell us in a sentence or two why you chose to be a member of APS, and we use your quote in the APS membership brochure, we will send you one item of your choice from the APS store."

Here is what I decided to write: I chose to join APS because my research as an applied mathematician also interfaces with numerous areas of physics (and I publish much of my work in physics journals), and I wanted to make sure that I am also part of the physics community. I was already playing ultimate frisbee with physicists in grad school, and this was the natural next step.

Do you think they'll use my quote?

Sunday, May 14, 2017

Patent Application (from 2012): "Devices and Implements for Deterring Monsters, Specters, Demons, and the Like"

This patent application, filed in 2012, is called "Devices and implements for deterring monsters, specters, demons, and the like".

Here is a choice excerpt: Devices and implements for staving off monsters, specters, demons and the like as imagined by a child at bedtime. A hand-held controller unit is provided having a user interface, which is capable of being used by the child under the bed covers of a bed. The hand-held controller unit may include any of a walkie-talkie capability, a flashlight capability, a nightlight capability, the capability to activate an external device, and other capabilities. At least one external device may be provided which is capable of being placed beneath the bed and is configured to be activated by the hand-held controller unit. At least one substantially hollow air-through member may be provided which is configured to facilitate airflow between underneath the bed covers of the bed and above the bed covers of the bed. A supplemental bed cover may be provided that is configured to be placed on the bed.

Personally, I am most afraid of "the like".

Also, the Google Patent listing says the patent was granted.

(Tip of the cap to the Improbable Research Blog.)

Saturday, May 13, 2017

Museum Notice of the Day

Wow! This is spectacular!

(Tip of the cap to Meghan Duffy.)

Congratulations to Sandy Patel!

Support staff member Sandy Patel of University of Oxford's Mathematical Institute won the Oxford University Students Union award for best support staff. Congratulations!

Credit where it is due on two counts:

(1) Sandy is a very good member of support staff! I have interacted with support staff at many places, and good ones versus bad ones make a huge difference in academic experience. Sandy always stood out during my time at Oxford as one of the really good ones. The number of times I have told my students to 'Go ask Sandy Patel." (and similar) is very numerous indeed.

(2) And credit to my former employer (the Oxford Mathematical Institute) for publishing Sandy's award on their website and circulating it on Twitter. This type of recognition is almost always in the background and it shouldn't be. (I learned this from grad school, where we had the awesome Dolores Pendell, versus nearly everywhere else I have been.) We spend a lot of time bragging about the scientific accomplishments of faculty (and occasionally also their teaching accomplishments, though not enough), but we almost never publicize things when our support staff are excellent (though we do complain loudly when they're not), and we should!

Classic Typewriter Exhibit at San Fransisco International Airport

This is really cool!

The typewriter in the picture below is part of a current exhibit in terminal 2 of SFO airport.

Among the things I enjoyed when on sabbatical at Stanford were the really cool exhibitions at SFO. Among other things, this included one of classic boardgames.

Harry McCracken also posted pictures of several other typewriters from the exhibit on his Twitter feed. Take a look at this one, this one, this one, this one, and this one. This should be all of the typewriter pictures that he posted as part of this thread.

(Tip of the cap to Sydney Padua.)

Friday, May 12, 2017

Lyrical Repetition in Pop Music

Here is a cool article about lyrical repetition (and compression possibilities) in pop music and how it's changed over the last few decades.

I of course decided to look at how Depeche Mode stacks up, and I zoomed up on them as an individual artist.

From the song and artist library they used, Depeche Mode is listed as the band from the 1990s with the least repetitive lyrics, though it does only use a subset of their songs and it listed them in the 1990s instead of the 1980s. (Naturally, the employed songs span multiple decades.)

The most lyrically repetitive Depeche Mode song is very obvious.

(Tip of the cap to Taha Yasseri and I Fucking Love Data.)

Article Title of the Day: "Ex-bullfighter and Maths Genius Among Candidates Standing for Macron"

The title of this article is fantastic! (Note that the article preview on Facebook has a slightly different title, with "Female" before the word "ex-bullfighter".)

I had already heard that Cédric Villani is one of the candidates standing for Macron (and that itself is awesome!), but I really like the article title in this case.

Also, the second sentence in the article's description of Villani is amusing: Cédric Villani, 43, who in 2010 won the Fields medal, the equivalent of the Nobel prize in mathematics, will stand for Macron in a suburban Paris district. The mathematician is known for his dandy-ish looks, long hair and collection of floppy bow ties.

(Tip of the cap to Yves van Gennip for this specific article.)

Thursday, May 11, 2017

Live-Action "Balloon Fight"

Take a look at this cool video.

This reminds me of a game called Balloon Fight that I played many moons ago on my NES. This game was very underrated. (It is an excellent game!)

(Tip of the cap to Guillermo Valle Pérez.)

Sydney Padua is Awesome!

In case you didn't realize this (and in that case you're missing out), Sydney Padua is awesome!

Wednesday, May 10, 2017

Hiding and Sneaking in Bushes and in Barrels

It seems that Sean Spicer is trying to take a page out of the book of some video games, as he literally hid amongst bushes and behind a tall hedge to try to avoid reporters. Naturally, the internet has has a field day with this.

Here is a choice quote from the Washington Post article above: "White House press secretary Sean Spicer wrapped up his brief interview with Fox Business from the White House grounds late Tuesday night and then disappeared into the shadows, huddling with his staff near a clump of bushes and then behind a tall hedge. To get back to his office, Spicer would have to pass a swarm of reporters wanting to know why President Trump suddenly decided to fire the FBI director."

Her clearly did not play enough Zelda games as a child. Here is how to properly sneak past people while hiding in a barrel.

We continue to live in a Coen Brothers movie. It's like watching a train wreck in slow motion (from a seat on the train, unfortunately).

Update: I just noticed the following tweet.

Update (5/11/17): And then there's this beauty.

Update (5/12/17): This Garden Spicer is pretty damn funny. (Tip of the cap to Maria Satterwhite, though I believe she shared a different article about the same item.)

Is it Wrong to Publish in the Journal Complicity?

Note: There need not be anything inherently wrong with publishing a paper in the journal Complicity, despite its name.

Monday, May 08, 2017

"Standard", Oxford, Walken, and Shatner Commas

Hell yes!!!

WarGames: "Lunch Order"

The new xkcd makes me think of the movie WarGames (which I really ought to watch again), although I suppose it's more like the inverse of it.

The Imperial Pikachu March

Pikachus marching to the sound of "The Imperial March" is highly amusing! See for yourself!

Friday, May 05, 2017

Replacing "Big Data" by "Batman" in Tweets

This Twitter account takes tweets and replaces "Big Data" with "Batman". Hilarity ensues.

Here is an example.

(Tip of the cap to Esteban Moro.)

Wednesday, May 03, 2017

A Map Only a Topologist Would Love

OK, maybe not literally, but I do expect topologists to be fond of this map of the border between Belgium and The Netherlands at Baarle-Nassau.

Monday, May 01, 2017

Not The Twilight Zone, but The Brillouin Zone

It occurs to me that one should initially introduce the idea of a Brillouin zone to students as if it were narrated by Rod Serling in the style of The Twilight Zone. It might go something like this:

There is a primitive cell in reciprocal space beyond that which is known to undergraduates. It is a fundamental unit into which that space is divided. It can tile lattices as vast as space and as timeless as infinity. It leads to a sequence of disjoint equal-volume regions at increasing distances from the origin, and it lies between the pit of physicists' fears and the summit of their knowledge. This is the region of imagination. It is an area which we call THE BRILLOUIN ZONE.

Update: Joshua Bodyfelt produced a really nice picture after seeing my quote above on Facebook. Here it is.

An Amazing Short Cartoon

"Alike" is an amazing short cartoon that you should watch!

(I saw this on Facebook via a post with which one of my friends interacted. I don't remember the name of the poster.)

Friday, April 28, 2017

Lego Grad Student

I just found out about Lego Grad Student from a Facebook post by Shanti Rao.

I had never heard of Lego Grad Student before, but this brilliantly fills a gap in the online world. I'll include one of LGS's tweets in this blog entry.

"Persistent Homology of Time-Dependent Functional Networks Constructed from Coupled Time Series"

One of my papers came out in final form today. Here are the details.

Title: Persistent Homology of Time-Dependent Functional Networks Constructed from Coupled Time Series

Authors: Bernadette J. Stolz, Heather A. Harrington, and Mason A. Porter

Abstract: We use topological data analysis to study "functional networks" that we construct from time-series data from both experimental and synthetic sources. We use persistent homology with a weight rank clique filtration to gain insights into these functional networks, and we use persistence landscapes to interpret our results. Our first example uses time-series output from networks of coupled Kuramoto oscillators. Our second example consists of biological data in the form of functional magnetic resonance imaging data that were acquired from human subjects during a simple motor-learning task in which subjects were monitored for three days during a five-day period. With these examples, we demonstrate that (1) using persistent homology to study functional networks provides fascinating insights into their properties and (2) the position of the features in a filtration can sometimes play a more vital role than persistence in the interpretation of topological features, even though conventionally the latter is used to distinguish between signal and noise. We find that persistent homology can detect differences in synchronization patterns in our data sets over time, giving insight both on changes in community structure in the networks and on increased synchronization between brain regions that form loops in a functional network during motor learning. For the motor-learning data, persistence landscapes also reveal that on average the majority of changes in the network loops take place on the second of the three days of the learning process.

Thursday, April 27, 2017

Stunning Drawings of Seaweed

Margaret Gatty drew some gorgeous pictures of seaweed as part of her book on the topic. These pictures are awesome!

Tuesday, April 25, 2017

An Epic "Slide"

This "slide" by the Toronto Blue Jays' Chris Coghlan is absolutely epic.

(The link goes to a public Facebook post from Major League Baseball.)

Perceptions of the Probability of Ambiguous Statements

You can completely mess up this chart in the UK simply by using the word "quite". That will do quite an ambiguous number on the perceived probabilities.

(More seriously, I really like this visualization.)

Conway's Game of Life In Real Life (on an Ocellated Lizard)

Wow! This is amazing!

Here is the blurb on the Facebook post that goes with the Physics Today article (though I added the hyperlink): The ocellated lizard develops an intricate, ever-changing pattern of black and green spots when it matures. Now researchers have determined that the patterns on the animals' backs update according to a well-defined algorithm: Over a period of a month or so, a given scale will change color—from green to black or black to green—with a probability that depends on the colors of the scales around it. In essence, the reptile is the embodiment of a cellular automaton, a type of discretized model made popular by John Conway’s Game of Life and used to simulate the spread of wildfires, the firing of neurons, and other phenomena.

Physics Today's article is about a recent article in Nature called "A living mesoscopic cellular automaton made of skin scales".