Seismic noise subsoil in order to draw seismic microzonation maps showing the predicted ground response to earthquakes. Research on the origin of seismic noise indicates that the low frequency part of the spectrum (below 1 Hz) is due to natural causes, chiefly ocean waves. In particular the peak between 0.1 and 0.3 Hz is clearly associated with the interaction of water waves of nearly equal frequencies but opposite directions. At high frequency (above 1 Hz), seismic noise is mainly produced by human activities such as road traffic and industrial work; but there are also natural sources, like rivers. Around 1 Hz, wind
Prevalence effect of success and the stakes are low. Some searches combine low prevalence with high stakes; medical screenings such as mammography or cytopathology, is an important search for a target rarely present (typically under one percent). Missing a rare target, such as a weapon smuggled onto an airplane, may have serious consequences. The prevalence effect is influenced by top-down control of a future prospect or the bottom-up priming of past experience. Top-down refers to the expectation effect: knowledge of what will happen next. The bottom-up, repetition effect is produced by the sharing of properties by current and preceding stimuli. Observers may