Propagation of incoherently soliton pairs in photorefractive crystals under steady-state conditions is studied. These soliton states can be generated when the two mutually incoherent optical beams with the same polarization and wavelength incident on the biased photorefractive crystal. Such soliton pairs can exist in bright-bright, dark-dark, gray-gray as well as in bright-dark types. In this p...

Sexual cannibalism is a particularly extreme example of conflict between the sexes, depriving the male of future reproduction. Theory predicts that sexual conflict should induce counter-adaptations in the victim. Observations of male spiders mating with moulting and hence largely immobile females suggest that this behaviour functions to circumvent female control and cannibalism. However, we lac...

—Selection will favor males that can bias mating attempts towards more desirable females if the benefits of choosiness outweigh the costs of discrimination. Males that coexist with asexual and/or parasitically castrated females may benefit from discriminatory mating behavior because copulations with these females will not result in offspring that are related to the male. An example of a natural...

An important number of Sprague-Dawley males selected by strict inbreeding process for their high spontaneous yawing frequency (HY) fail to copulate after repeated exposure to receptive females. These HY males that fail to mate are called non-copulators (HYNC). The causes of this behavioral deficit are still unknown. The aim of the present study was to make a detailed behavioral characterization...

In this paper, using a relation between Schur multipliers of pairs and triples of groups, the fundamental group and homology groups of a homotopy pushout of Eilenberg-MacLane spaces, we present among other things some behaviors of Schur multipliers of pairs and triples with respect to free, amalgamated free, and direct products and also direct limits of groups with topological approach.