and described by the formula: where A is the amplitude of oscillation, f is the frequency, t is the elapsed time, and is the phase of the oscillation. The phase determines or is determined by the initial displacement at time t = 0. A motion with frequency f has period. Two potential ambiguities can be noted:
Incubation Period Shingles is not transmitted from exposure to another infected person so there is no applicable incubation period. Anyone who has recovered from varicella may develop shingles. Mode of Transmission Transmission of the virus occurs through direct contact with the rash or fluid from the lesions.
The early stage of shingles -- called the prodromal stage -- begins 3 to 4 days before the rash appears. Early symptoms resemble those of the common cold, including headache, nausea, general achiness, abdominal pain, fatigue, fever and chills. As shingles progresses, more severe symptoms begin to develop. The next stage of shingles is called the eruptive stage. Pain is usually the first symptom. For some, it can be excruciating and may include burning, itching, numbness or tingling in the area where the rash will form. The pain may be felt penetrating from front to back, especially in the chest or face.