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.

On Monday, after a long quarter-century, West Virginians said goodbye to their state's 6 percent food tax. Now to see what, if any, business we've been missing. In 1989, retailers warned that sales in West Virginia would go down if legislators imposed a 6 percent tax on food. "Whatever they put on would be passed on to the consumer," Charles Forth, who owned supermarkets in both West Virginia and Ohio, told the newspaper in February 1989. "Six percent is $6 on $100. That will make a difference when people are already hurting and trying to make ends meet." It's a lot easier to drive customers away than to win them back, a fact legislators should bear in mind when it comes to taxation.

The Vikings were seafaring north Germanic people who raided, traded, explored, and settled in wide areas of Europe, Asia, and the North Atlantic islands from the late 8th to the mid-11th centuries. The Vikings employed wooden longships with wide, shallow-draft hulls, allowing navigation in rough seas or in shallow river waters. The ships could be landed on beaches, and their light weight enabled them to be hauled over portages. These versatile ships allowed the Vikings to travel as far east as Constantinople and the Volga River in Russia, as far west as Iceland, Greenland, and Newfoundland, and as far south as Nekor. This period of Viking expansion, known as the Viking Age, constitutes an important element of the medieval history of Scandinavia, Great Britain, Ireland, Russia, and the rest of Europe.

Conan of Aquilonia is a collection of four linked fantasy short stories written by L. Sprague de Camp and Lin Carter featuring Robert E. Howard's seminal sword and sorcery hero Conan the Barbarian. The stories were originally published in Fantastic for August 1972, July 1973, July 1974, and February, 1975. The collected stories were intended for book publication by Lancer Books, but this edition never appeared due to Lancer's bankruptcy. The first book edition was issued in paperback by Ace Books in May 1977 and the first British edition was published by Sphere Books in October 1978.

Plasma is one of the four fundamental states of matter (the others being solid, liquid, and gas). Heating a gas may ionize its molecules or atoms (reducing or increasing the number of electrons in them), thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions.