Smell genes must wander

Whither must spermatozoa wander? The future of laboratory seminology.

This commentary celebrates the publication of the 5th edition of the World Health Organization Laboratory Manual for the Examination and Processing of Human Semen. This is the most complete text to date on the creation of a conventional semen profile and includes invaluable reference limits for specific aspects of semen quality based on the analysis of over 1 900 recent fathers. The new edition...

Stimulating minds to wander.

Springing from memory and imagination, mind wandering is a mental state occupying as much as half of our waking life, involving a shift of attention away from the external environment and toward task-unrelated concerns (1). Although mind wandering may play an important role in planning and creativity (2, 3), it is also widely associated with negative mood and degraded performance on measures of...

True polar wander and supercontinents

I present a general model for true polar wander (TPW), in the context of supercontinents and simple modes of mantle convection. Old, mantle-stationary supercontinents shield their underlying mesosphere from the cooling effects of subduction, and an axis of mantle upwelling is established that is complementary to the downwelling girdle of subduction zones encircling the old supercontinent. The u...

To smell or not to smell? That is the question!

Theoretical constraints on true polar wander

[1] For the present geologic epoch, true polar wander (TPW) is relatively small, but simple theoretical considerations suggest that it could have been larger in other epochs. In this work, we use scaling arguments to assess the qualitative behavior of TPW and a simple Maxwell model to analytically describe how changes in mass anomalies translate into TPW. Unlike previous work, we derive simple ...