New Caledonian (NC) crows are the most sophisticated tool manufacturers other than humans. The diversification and geographical distribution of their three Pandanus tool designs that differ in complexity, as well as the lack of ecological correlates, suggest that cumulative technological change has taken place. To investigate the possibility that high-fidelity social transmission mediated this ...

Cultural evolution is a complex process that can happen at several levels. At the level of individuals in a population, each human bears a set of cultural traits that he or she can transmit to its offspring (vertical transmission) or to other members of his or her society (horizontal transmission). The relative frequency of a cultural trait in a population or society can thus increase or decrea...

The evolution of virulence was studied in a virus subjected to alternating episodes of vertical and horizontal transmission. Bacteriophage f1 was used as the parasite because it establishes a debilitating but non-fatal infection that can be transmitted vertically (from a host to its progeny) as well as horizontally (infection of new hosts). Horizontal transmission was required of all phage at s...

High-speed maglev train is considered an ideal vehicle in the 21st Century, as an important part of the train, the travel mechanism bears and delivers a variety of vertical and horizontal alternating load in operation, it affects the operation safety of the train directly, so key components of the travel mechanism should under fatigue strength test by fatigue test machine.The paper proposed a v...

We measured the eye movements of three sisters with Niemann-Pick type C disease who had a selective defect of vertical saccades, which were slow and hypometric. Horizontal saccades, and horizontal and vertical pursuit and vestibular eye movements were similar to control subjects. The initial movement of oblique saccades was mainly horizontal and most of the vertical component occurred after the...

We compared horizontal and vertical smooth pursuit eye movements in five healthy human subjects. When maintenance of pursuit was tested using predictable waveforms (sinusoidal or triangular target motion), the gain of horizontal pursuit was greater, in all subjects, than that of vertical pursuit; this was also the case for the horizontal and vertical components of diagonal and circular tracking...