Caught in the rhythm

The controllability of cardiac rhythm in elderly

Introduction: Recent reports have shown that rare fluctuations in cardiac cycles are ‘forgotten’ quickly in healthy individuals and it is possible to quantify the “memory length” of a physiological time-series using an inverse statistical approach. Methods: In the present study, we assessed the effect of aging on memory length in cardiac rhythm. Results: There was a long...

Caught in the act

Along with replication and mutability, living beings are set apart from the mineral background they inhabit by their metabolism—their ability to catalyse chemical reactions. Since Linus Pauling first proposed that these reactions are made pos­ sible by enzymes that recognize and bind tightly to their substrates at a crucial transi­ tion point [1], it has become increasingly clear that understan...

Caught in the Act?

Galaxies are thought to be surrounded by massive halos of dark matter, each outweighing its galaxy by a factor of about eight. The visible part of a galaxy, occupying the inner 10% of the halo, consists of a mixture of stars and gas. Galaxies harbour a giant black hole at their centres, which in some cases is actively fuelled as it sucks in surrounding gas. In especially active galaxies, called...

Caught in the act

The crystal structure of a HECT E3 enzyme has been captured as it transfers ubiquitin to a target protein, revealing the dramatic changes in shape that enable it to modify particular residues in its targets.

Caught in the Middle