The Doppler effect (or Doppler shift), named after the Austrian physicist Christian Doppler, who proposed it in 1842 in Prague, is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession.

The Los Angeles County Department of Animal Care and Control (ACC) is one of the largest and most progressive animal control agencies in the United States. The ACC operates six animal shelters serving all unincorporated County areas and 50 contract cities. The ACC covers more than 3,200 square miles of cities, deserts, beaches, and mountains; from the Antelope Valley in the north to the Palos Verdes Peninsula in the south; as far east as the border of San Bernardino County and west all the way to Thousand Oaks. The ACC provides animal control and rescue services 24 hours a day, seven days a week in our service area.

A perennial stream or perennial river is a stream or river (channel) that has continuous flow in parts of its stream bed all year round during years of normal rainfall. "Perennial" streams are contrasted with "intermittent" streams which normally cease flowing for weeks or months each year, and with "ephemeral" channels that flow only for hours or days following rainfall.

A utility cooperative is a type of cooperative that is tasked with the delivery of a public utility such as electricity, water or telecommunications to its members. Profits are either reinvested for infrastructure or distributed to members in the form of "patronage" or "capital credits", which are essentially dividends paid on a member's investment into the cooperative. Each customer is a member and owner of the business with an equal say as every other member of the cooperative, unlike investor-owned utilities where the amount of say is governed by the number of shares held.

"Give me your tired, your poor, your huddled masses yearning to breathe free, the wretched refuse of your teeming shore. Send these, the homeless, tempest-tossed, to me. I lift my lamp beside the golden door." - Emma Lazarus, inscription for the Statue of Liberty