Eight counts to a measure. The clave rhythm has two pulse beats to a bar. This refers to a constant in the music that keeps all the instruments in a band in time and in the same pattern - it is that part of the music, to which you tend to tap your foot. The pulse is generated by the sound of a single strike of a drum on a count continuing to be heard on the next count. Salsa's pulse beats occur on the first and third counts and might be provided by the drummer playing the bell of the ride cymbal or be carried in the base line of the music.
Accents can occur on the count or anywhere in between.
It depends on what type of music is being played and the feel the musicians are after. Thus, for a particular instrument, a bar of music is divided into resonances with accent markers and rests. Rests describe the duration that an instrument remains silent. The resonance of a note can start on or before a count and extend beyond it. Accents emphasise a note played by a particular instrument and are used to give feel to the music.