Tacoma Narrows Bridge (1940) Billah and Scanlan (1991) reported that in fact, many physics textbooks (for example Resnick et al. and Tipler et al.) wrongly explain that the cause of the failure of the Tacoma Narrows bridge was externally forced mechanical resonance. Resonance is the tendency of a system to oscillate at larger amplitudes at certain frequencies, known as the system's natural frequencies. At these frequencies, even relatively small periodic driving forces can produce large amplitude vibrations, because the system stores energy. For example, a child using a swing realizes that if the pushes are properly timed, the swing can move with a very
Large irregular activity EEG, the non-rhythmic pattern of large irregular activity,(LIA). LIA has the predominant pattern of large amplitude slow waves that contain some fluctuations of sharp spikes (sharp waves) of 50–100 ms duration. The predominant frequency of LIA is slower than that of theta waves. LIA is often accompanied by ripples in the pyramidal cell layer. When the neural circuitry of the hippocampus is activated it tends to oscillate at theta frequencies. It has also been noted that a fair proportion of hippocampal neurons fire in a correlation with sharp wave activity. The theta state is thought to be involved in the