In a “normal” electrocardiogram (ECG), the transition of the QRS axis in the precordial leads occurs between leads V 3 and V 4 (i.e., there is a dominant S in V 3 and a dominant R in V 4).

About half of all spiral galaxies appear to be rotating clockwise and the other half counterclockwise. The direction a galaxy rotates depends on your perspective. As an analogy, consider a spinning ...

Scientists have uncovered a new explanation for how swimming bacteria change direction, providing fresh insight into one of biology's most intensively studied molecular machines.

Researchers have unseated a previous theory for the mechanism underlying bacterial flagella movement, changing our ...