Horizontal black surfaces are usually very attractive to polarotactic aquatic insects, since they generally reXect highly and horizontally polarized light, and thus imitate water surfaces. We monitored highly polarizing black burnt-up stubble-Welds, but surprisingly never found aquatic insects or their carcasses in the ash, although Xying polarotactic insects were abundant in the area, which we...

Apparent horizons are structures of spacelike hypersurfaces that can be determined locally in time. Closed surfaces of constant expansion (CE surfaces) are a generalisation of apparent horizons. I present an efficient method for locating CE surfaces. This method uses an explicit representation of the surface, allowing for arbitrary resolutions and, in principle, shapes. The CE surface equation ...

Fungal spores are continuously deposited on the leaf surfaces by wind impaction, sedimentation and rain wash-out from the atmosphere and splash-dispersal. They reside and act as asymptomatic mutualists, benign commensals or latent pathogens. A slight imbalance in this relation can lead to pathogenic phase of the fungi, resulting in a variety of symptoms on leaves viz. discoloration, blight, soo...

A property well known as the first law of black hole is a relation among infinitesimal variations of parameters of stationary black holes. We consider a dynamical version of the first law, which may be called the first law of black hole dynamics. The first law of black hole dynamics is derived without assuming any symmetry or any asymptotic conditions. In the derivation, a definition of dynamic...