John C. Baez's Blog, page 66

Periodic Patterns in Peptide Masses

Gheorghe Craciun is a mathematician at the University of Wisconsin who recently proved the Global Attractor Conjecture, which since 1974 was the most famous conjecture in mathematical chemistry. This week he visited U. C. Riverside and gave a talk on this subject. But he also told me about something else—something quite remarkable.

The mystery

A peptide is basically a small protein: a chain of made of fewer than 50 amino acids. If you plot the number of peptides of different masses found in...

Applied Category Theory

The American Mathematical Society is having a meeting here at U. C. Riverside during the weekend of November 4th and 5th, 2017. I’m organizing a session on Applied Category Theory, and I’m looking for people to give talks.

The goal is to start a conversation about applications of category theory, not within pure math or fundamental physics, but to other branches of science and engineering—especially those where the use of category theory is not already well-established! For example, my studen...

Jobs at U.C. Riverside

The Mathematics Department of the University of California at Riverside is trying to hire some visiting assistant professors.
We plan to make decisions quite soon!

The positions are open to applicants who have PhD or will have a PhD by the beginning of the term from all research areas in mathematics. The teaching load is six courses per year (i.e. 2 per quarter). In addition to teaching, the applicants will be responsible for attending advanced seminars and working on research projects.

This...

Restoring the North Cascades Ecosystem

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In 49 hours, the National Park Service will stop taking comments on an important issue: whether to reintroduce grizzly bears into the North Cascades near Seattle. If you leave a comment on their website before then, you can help make this happen! Follow the easy directions here:

http://theoatmeal.com/blog/grizzlies_north_cascades

Please go ahead! Then tell your friends to join in, and give them this link. This can be your good deed for the day.

But if you want more details:

Grizzly bears are...

Pi and the Golden Ratio

Two of my favorite numbers are pi:

and the golden ratio:

They’re related:

Greg Egan and I came up with this formula last weekend. It’s probably not new, and it certainly wouldn’t surprise experts, but it’s still fun coming up with a formula like this. Let me explain how we did it.

History has a fractal texture. It’s not exactly self-similar, but the closer you look at any incident, the more fine-grained detail you see. The simplified stories we learn about the history of math and phy...

Saving Climate Data (Part 6)

Scott Pruitt, who filed legal challenges against Environmental Protection Agency rules fourteen times, working hand in hand with oil and gas companies, is now head of that agency. What does that mean about the safety of climate data on the EPA’s websites? Here is an inside report:

• Dawn Reeves, EPA preserves Obama-Era website but climate change data doubts remain, InsideEPA.com, 21 February 2017.

For those of us who are backing up climate data, the really important stuff is in red near the b...

Azimuth Backup Project (Part 4)

The Azimuth Climate Data Backup Project is going well! Our Kickstarter campaign ended on January 31st and the money has recently reached us. Our original goal was $5000. We got $20,427 of donations, and after Kickstarter took its cut we received $18,590.96.

Next time I’ll tell you what our project has actually been doing. This time I just want to give a huge “thank you!” to all 627 people who contributed money on Kickstarter!

I sent out thank you notes to everyone, updating them on our progre...

Saving Climate Data (Part 5)

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There’s a lot going on! Here’s a news roundup. I will separately talk about what the Azimuth Climate Data Backup Project is doing.

I’ll start with the bad news, and then go on to some good news.

Tweaking the EPA website

Scientists are keeping track of how Trump administration is changing the Environmental Protection Agency website, with before-and-after photos, and analysis:

• Brian Kahn, Behold the “tweaks” Trump has made to the EPA website (so far), National Resources Defense Council blo...

Information Geometry (Part 16)

This week I’m giving a talk on biology and information:

• John Baez, Biology as information dynamics, talk for Biological Complexity: Can it be Quantified?, a workshop at the Beyond Center, 2 February 2017.

While preparing this talk, I discovered a cool fact. I doubt it’s new, but I haven’t exactly seen it elsewhere. I came up with it while trying to give a precise and general statement of ‘Fisher’s fundamental theorem of natural selection’. I won’t start by explaining that theorem, since my...

Biology as Information Dynamics

This is my talk for the workshop Biological Complexity: Can It Be Quantified?

• Biology as information dynamics.

Abstract. If biology is the study of self-replicating entities, and we want to understand the role of information, it makes sense to see how information theory is connected to the ‘replicator equation’—a simple model of population dynamics for self-replicating entities. The relevant concept of information turns out to be the information of one probability distribution relative...