An oil tanker, also known as a petroleum tanker, is a merchant ship designed for the bulk transport of oil. There are two basic types of oil tankers: the crude tanker and the product tanker. Crude tankers move large quantities of unrefined crude oil from its point of extraction to refineries. Product tankers, generally much smaller, are designed to move petrochemicals from refineries to points near consuming markets.

Since 1944, the County of Los Angeles Department of Parks and Recreation has been meeting the diverse needs of not only residents, but also visitors from around the world. With over 63,000 acres of parks, gardens, lakes, trails, natural areas, and the world's largest public golf course system, the Department of Parks and Recreation is committed to providing the public with social, cultural, and recreational activities to enjoy the whole year.

Volunteer hosts went to the airport, picked up assigned students, fed them dinner, took them to the opening lecture at the Clay Center, put them in spare bedrooms for the night, then fed them breakfast this morning and will deliver the outstanding teens to buses that convey them to the mountain retreat where they undergo a month of intensive science training and outdoor fun.

Luckily, this year, enough local families volunteered to host all the brilliant youths. In the past, the number of guest homes sometimes fell short, and some of the visitors slept on cots and sleeping bags at local churches. They're adventurous teens and don't mind this makeshift camp-in but it's better if friendly hosts give them a more personal welcome for their stay.

Pragmatism is a philosophical tradition that began in the United States around 1870. Pragmatism is a rejection of the idea that the function of thought is to describe, represent, or mirror reality. Instead, pragmatists develop their philosophy around the idea that the function of thought is as a instrument or tool for prediction, action, and problem solving. Pragmatists contend that most philosophical topics - such as the nature of knowledge, language, concepts, meaning, belief, and science - are all best viewed in terms of their practical uses and successes rather than in terms of representative accuracy.

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.