Role of the cell wall on the expression of osmotic-sensitive (os-1) and temperature-sensitive (cot-1) phenotypes of N. crassa. A comparative study on mycelial and wall-less phenotypes of the slime variant

Ascospore segregants ( slime -like) of the triple mutant fz(fuzzy);sg(spontaneous germination) os-1(osmotic) ( slime ; Emerson 1963. Genetica 34:162-182) of Neurospora crassa germinate as a plasmodium which, after some time, results in a morphologically abnormal mycelium. If the mycelium of a slime -like isolate is cultured under high osmotic pressure (Nelson et al. 1975. Neurospora Newsl. 22:15-16), it releases cells lacking walls which proliferate as spheroplasts

Evidence of Weight-Based Representations of Gravitational Motion

A hypothesis gaining increasing popularity is that laypeople’s representations of physical phenomena might be driven by internalized physical laws. In three experiments, we tested if such hypothesis holds true for the representation of gravitational motion. Participants were presented with realistic, real-scale virtual spheres falling vertically downward from about 2 m high. The spheres appeared to be made of either polystyrene or wood. In Experiment 1, participants adjusted the falling motion pattern until it appeared to be natural. In Experiment 2, they compared the perceived naturalness of vertical free falls in a vacuum with the perceived naturalness of more realistic falls characterized by the presence of air drag. In Experiment 3, they estimated the position of the sphere after a variable interval of time from the beginning of the fall. Inconsistently with predictions from physics, results showed that representations of gravitational motion were strongly affected by the implied masses of the falling objects and did not account for air drag. This provides support for the hypothesis of weight-based heuristic representations of gravitational motion against the hypothesis of the internalization of physical laws