A low-pass filter passes low-frequency components of signals while attenuating higher frequencies. Gaussian blur is a low-pass filter, attenuating high frequency signals. This displaces the agonist, attenuating or reversing the agonist effects. Mangroves naturally encourage sediment deposition by slowing currents and attenuating waves. VC2 encodes two attenuating mutations that together reduce HSV entry into neurons. Thin sheets of aluminium are not very effective at attenuating low-frequency magnetic fields. The David Clark Company pioneered aeronautical equipment including anti-gravity suits and noise attenuating headsets. Ectopic thyroid tissue appears as a well-circumscribed, homogeneous, highly attenuating mass relative to adjacent muscles. This was done principally as a levelling and sound attenuating layer. The Pelamis is an attenuating wave energy converter. One such drug that has been shown to have attenuating effects on reinstatement is mecamylamine. On the outward motion, the rovings are paid out through attenuating rollers and twisted. However, the idea of attenuating a virus through serial passage still holds. The L21 was replaced by the Attenuating Energy Projectile in June 2005.