September 13, 2017 at 04:07AM

Today I Learned: 1) ...dependency graphs matter. Bungie's Chris Butcher has a wonderful talk on asset processing for the game Destiny. In short, Bungie built a nifty asset compiler that let them build, on a PC, a compressed binary of the game so that developers and artists could check out their changes, in a final context, with the game's final memory layout. The problem was, the system made it really easy to link together dependencies. Imagine, for example, that some object (perhaps a system that highlights enemies) wants to know the bounding box for a crate. The compilation system then would go compile the crate and return the bounding box. But wait! In compiling down the crate, the system would need to know about the shader used by that crate. So it would compile the shader, too. Which would mean compiling every object used by the shader. And so on. Basically, it was really, really easy to end up compiling the ENTIRE LEVEL any time an artist made any change, which meant that artists would have to wait hours to see the results of every change. Not cool. The lesson? Compilation dependencies are dangerous things, especially if you let people who don't understand them VERY well start to add them. For more details, see: https://www.youtube.com/watch?v=7KXVox0-7lU 2) Lamins are a class of protein that's critical to the proper formation of the nuclear lamina, which is a sheet of proteins that coats the inside of the nucleus's plasma membrane. The nuclear lamina is really important for proper DNA spatial organization and replication. If you have missing or malformed lamins, you get progeria. Today I learned that lamins are unique to animals. Plants, fungi, and protsts don't have lamins. They DO have nuclear lamina -- they're just made with different proteins. 3) Speaking of lamins, today I learned that lamins and laminins are NOT THE SAME THING. *Lamins* structure the *nuclear lamina*. *Laminins* are the primary component of *basal lamina*, which is a layer of mixed proteins and glycoproteins (proteins with sugars attached) and polysaccharide (sugars linked in long chains) that coat the surface of animal cells and form the basal layer of most connective tissue. Also, today I learned about the basal lamina. I'm sure I've encountered it in some bio class along the way, but I never really got what it was, and how it differs from any other extracellular matrix. In short, the extracellular matrix is bulky, where the basal lamina is sheet-like and typically sticks directly to a layer of cells. They're also made from different proteins, but I don't understand the consequences of those differences yet.