The Arts and the Age of the Chip

This chapter provides the capstone to this book’s argument that humankind has adopted quantification as a worldview. It describes how quantification has permeated our lives, far beyond just academic formulas to all domains, whether mathematical or otherwise. Examples are given first from the intersection of mathematics and art in da Vinci’s drawings. Next, the connection between mathematics and music is made, with a discussion of J. S. Bach’s The Well-Tempered Clavier and music theory’s circle of fifths. The chapter then provides an elementary explanation of artificial intelligence (or AI, as it is commonly known) with Bayesian logic, and a discussion of Nick Bostrom’s idea’s that the possibility of a computer having “superintelligence” poses a supreme danger to humanity. In addition, the chapter describes Max Tegmark’s innovative work in astrophysics and his belief in a wholly mathematical universe as part of a larger four-system multiverse.

Local decondensation at double-stranded DNA breaks modifies chromatin at long distances and reduces encounter times during homology search

Double-strand break (DSB) repair by homologous recombination (HR) requires an efficient and timely search for a homologous template. Here we first study global chromatin re-organization following a single DSB: due to the potential release of cross-linkers such as cohesin and CTCF molecules near the DSB site, loops are released and chromatin is decondensed, explaining the change of chromatin locus motion at larger genomic distances. This mechanism provides an elementary explanation for the increase of the anomalous exponent at sites located far away from the DSB, after break induction. Second, we explore the consequences of chromatin reorganization for the homology search during DNA repair: using polymer models, we estimate the mean first encounter time (MFET) between two loci on the chromatin in a confined nucleus. Reducing tethering forces, as reported experimentally on chromatin, is associated with a local decondensation near the break followed by the extrusion of the breaks. Consequently, we report here that the mean first encounter time between homologous sites is decreased by two orders of magnitude even when the homologue sequence is located on the nuclear boundary. To conclude, our results suggest that local changes in inter-nucleosomal contacts near DSBs, by cohesin removal, remodel the chromatin and drastically shorten the time required to complete a long-range search for a homologous template.

Things You Can Try: Diagonally magic square arrays

Here is a simple procedure that gives mystifying, magic results, that have a very elementary explanation.