Erdös with a non-kosher side of Bacon

Erdös number

Paul Erdös was a prolific and important mathematician. He also had hundreds of collaborators from around the world who coauthored papers with him.

Years ago, Casper Goffman explained an idea, called the Erdös number, that describes the “collaborative distance” between Erdös and someone else, where that distance is defined by the smallest number of steps based on coauthored papers. Erdös himself has an Erdös number of 0, while the 511 mathematicians who wrote papers with Erdös have an Erdös number of 1. One of these people is Persi Diaconis, a professional magician and Stanford mathematician specializing in probability theory.

Over 9,000 people have Erdös numbers of 2, meaning they wrote a paper with one or more of Erdös’s coauthors but never wrote a paper with Erdös himself.  Two of these people are Berkeley professors Bernd Sturmfels, in the field of algebraic geometry, and Lior Pachter, a computational biologist.  (Sturmfels coauthored three papers with Diaconis, and he wrote other papers with two more people with Erdös numbers of 1.  Pachter wrote several papers with mathematician Daniel Kleitman, an Erdös coauthor.)

In 2007, I coauthored a paper with Pachter and Sturmfels in which we analyzed epistatic interactions to describe the geometric structure of a fitness landscape:

Beerenwinkel, N., L. Pachter, B. Sturmfels, S. F. Elena, and R. E. Lenski. 2007. Analysis of epistatic interactions and fitness landscapes using a new geometric approach. BMC Evolutionary Biology 7:60.

So that paper gives me an Erdös number of 3.

Bacon number

A group of students later came up with the idea of a Bacon number, a Hollywood version of the Erdös number that equals the smallest number of film links separating any other actor from Kevin Bacon. (Bacon had been previously described as the “center of the Hollywood universe” after a 1994 interview in which he said he worked with everybody in Hollywood or someone who’s worked with them, according to Wikipedia.)

So Kevin Bacon has a Bacon number of 0, while actors who have appeared in a film with him have Bacon numbers of 1. An actor who appeared in a film with any actors who appeared with Bacon, but not in a film with Bacon himself, have a Bacon number of 2.

Morgan Freeman has a Bacon number of 1 based on a 2013 documentary film called “Eastwood Directs: The Untold Story.” (You missed that one? Me, too.) Well, a couple of weeks ago, I appeared in an episode of the show “Through the Wormhole with Morgan Freeman.”

Erdös-Bacon number

Now there’s a really special number called the Erdös-Bacon number, which is the sum of a person’s Erdös and Bacon numbers. Not many people have an Erdös number, and not many have a Bacon number. And very few people have an Erdös-Bacon number because you have to have written a math or science paper and appeared in a film, and of course with known connections to Erdös and Bacon along both paths.

Cornell mathematics professor Steven Strogatz has an Erdös-Bacon number of just 4, having appeared in a TV documentary film with Kevin Bacon called “Connected: The Power of Six Degrees.” Of course, that film is about the very sort of mathematical links we’re talking about here!

So someone just suggested to me that I now have an Erdös-Bacon number of 5. If so, that would put me ahead of such luminaries as Carl Sagan and Richard Feynman! Awesome!!

The fine print

As I was looking into this exciting possibility, I discovered a website called “The Oracle of Bacon.” It seems to be the semi-official arbiter of Bacon numbers, and it says: “We do not consider links through television shows, made-for-tv movies, writers, producers, directors, etc.”

That documentary about Cliff Eastwood, with both Morgan Freeman and Kevin Bacon in it, apparently doesn’t qualify.  So Morgan Freeman’s Bacon number rises to 2 (via many different paths through his many major films).

Even worse, though, my Bacon number evaporates entirely, since my link to Kevin Bacon goes through my appearance on a television show with Morgan Freeman.

So there you have it. I have an officially non-kosher Erdös-Bacon number of 5.

I guess I can live with that.

But if Kevin Bacon, Morgan Freeman, or any of their Hollywood friends invites me to appear in a real film, I’ll probably accept!


Note:  It looks like Steven Strogatz’s Erdös-Bacon number of 4 is also compromised because his Bacon number is through a TV movie.  You need to use non-default settings for it to show up on The Oracle of Bacon website.  But maybe it’s less non-kosher, since it was a TV movie, not just a TV show.


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A Wild Weekend

My wife Madeleine and I had a wild Memorial-day weekend.

Late Saturday afternoon, a dog found a baby squirrel, perhaps 5 or 6 weeks old, and chased it through our fence. The poor squirrel appeared to be in shock—its back was wet; it had probably been mouthed by the dog—but otherwise unharmed. We tried putting the baby squirrel on a protected tree branch in hopes that its mother would come and rescue it, but that did not happen and it did not budge … and nighttime was approaching.

So we brought the squirrel inside, and placed him in a secure container with rags to keep warm overnight. We hoped he would survive.

Indeed, the next morning, little “Nutcase” was dry and warm and, while still scared, on close inspection he seemed healthy and acting much stronger. You can see me holding him in the picture below.

On Sunday, we found a local wildlife rescue shelter that already had 20 other baby squirrels. There’s evidently been a bumper crop of the little fellas this year. Rearing them with others of their species, and with appropriate food and shelter, gives the foundlings a better chance of surviving when they are released back into the wild. Good luck, little Nutcase!

That wasn’t the end, though, of our wild weekend. On Monday, as Madeleine helped our daughter clean a garden shed, they disturbed a mother deer mouse living in a lawn-care bag with seven nursing pups.

The bag had been moved outside the shed before the mice were discovered. Mama mouse ran and, along with one of the pups, she hid right next to the bag inside a dense roll of wire fencing, the type used to protect young trees from browsing deer. But mama mouse did not abandon her pups!

We moved the other six pups and the nesting material into a more suitable container back inside the shed. We also carried the roll of wire fencing, along with mama mouse and that one pup, back into the shed. The next challenge—and it took us a couple of hours—was to coax mama mouse and that pup out of the fencing and into the container with the other six pups.

Success! Mama mouse was reunited with all her babies, and she promptly set out to nurse them. We gave her some bits of fruit and nuts, and a jar lid with water, to help her get over her stress and back to her work raising her family.

It’s amazing how invested one gets in helping wildlife survive, especially after meeting them “in person.”

REL and Nutcase, May 2015

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Tiny Things that Live in Little Bottles

As I mentioned in my previous post, it can be a fun challenge to explain your scientific research to people who aren’t scientists.

A week or so ago I came across a website that challenges you to explain something complicated using only the thousand most commonly used words.

So here’s my effort about our long-term evolution experiment with E. coli:

My team works with really tiny things that live in little bottles. We watch the tiny things change over time – over a really long time. The tiny things that do the best have learned to eat their food faster and faster, before the other guys can eat their lunch, so to say.  Well, the tiny things don’t really learn, but it’s kind of like learning – and even better, the best ones pass along what they learned to their kids.  A really cool guy came up with the idea of how this works more than a hundred years ago. My team’s work shows he got it pretty much right. But there’s a lot of stuff he didn’t know, and we’re figuring that out, too.

Several other biologists followed up including Nicole King, Graham Coop, and Josie Chandler (the links are to the simple-words-only descriptions of their own research).

Give it a try, and add your contributions in the comments below!


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Through the Wormhole with Science Communication

As a scientist, I spend a lot of my time trying to communicate subtle ideas and complex results to other scientists who, to a first approximation, share my interests and vocabulary. When I’m not doing that, I also spend a fair bit of time teaching students who are learning about science and, in some cases, trying to become scientists.

But it can be fun and interesting to step outside the usual communication channels by trying to explain our scientific research to people who aren’t scientists or students.

Last fall, I was invited to explain our research on the show Through the Wormhole with Morgan Freeman. The show’s director Tony Lund spoke with me at length by phone, asking questions about scientific concepts, our work, my personal interests, etc.

Based on our conversation, Tony came up with several ideas for scenes to film, both inside and outside the lab. The people in my lab group organized the props and materials that we would need to film the scenes, and several of them also had cameo roles in the various scenes.

Tony then came to MSU, along with veteran cameraman Max Miller. They spent over 12 hours with me, filming scenes in a studio and the lab, and asking countless questions on and off camera. I was impressed by the combination of creativity and attention to detail they brought to this work. For me, it was both exciting and exhausting.

Tony then had to take the hours of film and edit it all down to just a few minutes, while adding interesting visuals and preparing the script for the distinctive style and perspective of the show’s host and narrator, Morgan Freeman.

You can see the fruit of everyone’s labor here, in this four-minute segment: Evolution is Like Poker.  (Or here on youtube.)

My lab’s portion of the show ran a bit longer than this clip, but this is the bulk of it. A lot of time and effort went into making those few minutes of the show, but I think it was well worth it. I understand the show has over a million viewers, and I hope some of them will have a better understanding of evolution, our place in nature, and the joy of science.

So thanks Tony Lund, Max Miller, Morgan Freeman, Kim Ward in MSU’s communication office, everyone who helped with logistics and production, and all the members of the team, past and present, who have kept the LTEE going … and going … and going.



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Great Week for MSU with Honors to Kay Holekamp and Sheng Yang He

It’s been a terrific week for Michigan State University!

Last week Kay Holekamp was elected to the American Academy of Arts & Sciences.

You can read about Kay’s work on the ecology, evolution, and behavior of hyenas here.

From the American Academy’s press release:

“Since its founding in 1780, the Academy has elected leading ‘thinkers and doers’ from each generation, including George Washington and Benjamin Franklin in the eighteenth century, Daniel Webster and Ralph Waldo Emerson in the nineteenth, and Margaret Mead and Martin Luther King, Jr. in the twentieth. The current membership includes more than 250 Nobel laureates and more than 60 Pulitzer Prize winners.”

And today Sheng Yang He was elected to the National Academy of Sciences.

You can read about Sheng Yang’s work on plant-microbe interactions here.

From the National Academy’s press release:

“The National Academy of Sciences is a private, nonprofit institution that was established under a congressional charter signed by President Abraham Lincoln in 1863. It recognizes achievement in science by election to membership, and — with the National Academy of Engineering, Institute of Medicine, and National Research Council — provides science, technology, and health policy advice to the federal government and other organizations.”

I’m so fortunate to have such talented colleagues. And to make things even better, Kay and Sheng Yang are really nice people!

Congratulations, Kay and Sheng Yang!!

Added April 29: MSU just posted a nice article about Kay Holekamp, with links in it to a couple of other MSU articles on her research.

Added May 1: MSU has now posted an article on Sheng Yang He’s work and election to the NAS.

Added May 1: Congratulations to another great MSU colleague, Jianguo (Jack) Liu, on his election to the American Philosophical Society!

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Thirty Years

No, the LTEE did not suddenly jump forward by almost 3 years. That milestone will be reached on February 24, 2018.

Next Friday is the end of the semester at MSU and, for me, it will mark 30 years that I’ve been on the faculty: six at UC-Irvine, and 24 here at MSU. (I also taught for one semester at Dartmouth as a sabbatical replacement, while I was doing a postdoc at UMass.)

Holy cow: 30 years. Where did all that time go?

Well, a lot of it was spent advising, supervising, and mentoring graduate students. And those have been some of the most interesting, enjoyable, and rewarding professional experiences that I can imagine.

In fact, this afternoon Caroline Turner defended her dissertation – congratulations Dr. Turner! Her dissertation is titled “Experimental evolution and ecological consequences: new niches and changing stoichiometry.” It contains four fascinating and meaty chapters, two on the interplay between evolutionary and ecological processes in the LTEE population that evolved the ability to grow on citrate, and two on evolved changes in the elemental stoichiometry of bacterial cells over experimental time scales.

Caroline is the 20th student to complete her Ph.D. with me serving as the advisor or co-advisor. Here they all are, with links to their professional pages or related sites.

  1. Felisa Smith, Ph.D. in 1991 from UC-Irvine.
  2. John Mittler, Ph.D. in 1992 from UC-Irvine.
  3. Mike Travisano, Ph.D. in 1993 from MSU.
  4. Paul Turner, Ph.D. in 1995 from MSU.
  5. Greg Velicer, Ph.D. in 1997 from MSU.
  6. Brendan Bohannan, Ph.D. in 1997 from MSU.
  7. Phil Gerrish, Ph.D. in 1998 from MSU.
  8. Farida Vasi, Ph.D. in 2000 from MSU.
  9. Vaughn Cooper, Ph.D. in 2000 from MSU.
  10. Danny Rozen, Ph.D. in 2000 from MSU.
  11. Kristina Hillesland, Ph.D. in 2004 from MSU.
  12. Elizabeth Ostrowski, Ph.D. in 2005 from MSU.
  13. Bob Woods, Ph.D. in 2005 from MSU.
  14. Dule Misevic, Ph.D. in 2006 from MSU.
  15. Gabe Yedid, Ph.D. in 2007 from MSU.
  16. Sean Sleight, Ph.D. in 2007 from MSU.
  17. Zack Blount, Ph.D. in 2011 from MSU.
  18. Justin Meyer, Ph.D. in 2012 from MSU.
  19. Luis Zaman, Ph.D. in 2014 from MSU. (Charles Ofria was the primary advisor.)
  20. Caroline Turner, Ph.D. in 2015 from MSU.

There are also 8 doctoral students at various stages currently in my group at MSU including Brian Wade (Ph.D. candidate), Mike Wiser (Ph.D. candidate), Rohan Maddamsetti (Ph.D. candidate), Alita Burmeister (Ph.D. candidate), Elizabeth Baird, Jay Bundy, Nkrumah Grant, and Kyle Card.

My own advisor – the late, great Nelson Hairston, Sr. – said that he expected his graduate students to shed sweat and maybe even occasional tears, but not blood. I would imagine the same has been true for my students.

Thirty years, holy cow. Time flies when you’re working hard and having fun!


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Window Dressing

The window to the lab has been updated, courtesy of Zack Blount.

62K window dressing

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