“Our big surprise was to discover that the key was not in how much retinoic acid was produced, but in how it was degraded,” says Monaghan. The team discovered that cells in the distal part of the limb, the wrist, are awash in an enzyme called CYP26B1, whose sole function is to destroy retinoic acid. In contrast, cells in the shoulder have hardly any of this enzyme, allowing retinoic acid to accumulate to high levels.

This difference creates a chemical gradient along the limb: lots of retinoic acid in the shoulder, little in the wrist. It is this gradient that informs cells of their exact location.

This is fascinating on several levels. First, just the idea that there is a possibility that humans have an ability to regenerate limbs is amazing. Second, this reminds me that chemical gradients, which are mathematics at their core, play an important role in so many aspects of biology and medicine. And lastly, this really shows the possibilities unlocked by public funding of basic research. Kudos to Wired for reporting this, in a thorough manner, to a broader audience.

Here’s the original Nature paper.

tags: science research math medicine

posted by matt in Tuesday, June 17, 2025

In 2021, Koh came across a paper that discussed how to grapple with chaotic orbits from the perspective of symplectic geometry, an abstract field of math that is generally far removed from messy real-world details. She started to suspect that symplectic geometry might have the tools she needed to better understand orbits, and she got in touch with Agustin Moreno, the author of the paper. Moreno, then a postdoctoral fellow at Uppsala University in Sweden, was surprised and pleased to hear that someone at NASA was interested in his work. “It was unexpected, but it was also quite interesting and sort of motivating at the same time,” he said.

This is the beauty of pure academic research – someone makes an unforeseen connection and our collective knowledge grows. You never know how people will apply your work later. Pretty neat and compelling example of the value of basic research.

tags: research math science space

posted by matt in Sunday, May 5, 2024

All moved in! This was probably the easiest move yet. Jonathan has thinned his belongings a bit, and we're getting a little better at the process. Easy parking helped, too. All in all, the process was smooth and easy. He's ready to start his senior year.

He simplified the chalkboard this year, too, which really simplified things. We left the old one at home and bought four chalkboard panels at Home Depot. A few heavy duty command strips on the backside appear to hold everything just fine. He's going to let this first one sit for a few days to make sure, then will hang the others. He even tested the first one out right after hanging it, writing out the equation he worked to prove in his research over the summer.

One load for the apartment stuff, btw. We've got Renee's new Tesla Model Y, which is surprisingly spacious.

tags: harvard dorm math

photo posted by matt in Saturday, September 2, 2023

No one expects further progress to come easily; but that has never deterred Milman and Neeman. “From my experience,” Milman said, “all of the major things that I was fortunate enough to be able to do required just not giving up.”

The problem here is fascinating, and I can grasp that. I can't grasp the math of the solution, but I know somebody who can and I look forward to talking to him about it.

I love the closing paragraph quoted above. True in math, true in everything. Don't give up. Ever.

tags: academia math

posted by matt in Sunday, May 7, 2023

We arrived at Jonathan's dorm at about 11. He had a busy night.

tags: harvard math

photo posted by matt in Sunday, August 28, 2022

This is the crumpled sheet paper.

tags: science physics math

posted by matt in Sunday, March 14, 2021

I don't fully understand the math involved, but I appreciate the significance of the advance made here. And the potential practical applications are interesting - the author sees a role for it in weather predictions...and climate change

tags: math ai weather climatchange

posted by matt in Thursday, November 5, 2020