Six hours after landing at 4:17 p.m. Eastern Daylight Time (with less than 30 seconds of fuel remaining), Neil A. Armstrong took the “Small Step” into our greater future when he stepped off the Lunar Module, named “Eagle,” onto the surface of the Moon, from which he could look up and see Earth in the heavens as no one had done before him.

He was shortly joined by “Buzz” Aldrin, and the two astronauts spent 21 hours on the lunar surface and returned 46 pounds of lunar rocks. After their historic walks on the Moon, they successfully docked with the Command Module “Columbia,” in which Michael Collins was patiently orbiting the cold but no longer lifeless Moon.

A laser consists of a gain medium inside a highly reflective optical cavity, as well as a means to supply energy to the gain medium. The gain medium is a material with properties that allow it to amplify light by stimulated emission. In its simplest form, a cavity consists of two mirrors arranged such that light bounces back and forth, each time passing through the gain medium. Typically one of the two mirrors, the output coupler, is partially transparent. The output laser beam is emitted through this mirror.

An index term, subject term, subject heading, or descriptor, in information retrieval, is a term that captures the essence of the topic of a document. Index terms make up a controlled vocabulary for use in bibliographic records. They are an integral part of bibliographic control, which is the function by which libraries collect, organize and disseminate documents. They are used as keywords to retrieve documents in an information system, for instance, a catalog or a search engine. A popular form of keywords on the web are tags which are directly visible and can be assigned by non-experts also. Index terms can consist of a word, phrase, or alphanumerical term. They are created by analyzing the document either manually with subject indexing or automatically with automatic indexing or more sophisticated methods of keyword extraction. Index terms can either come from a controlled vocabulary or be freely assigned.

Trying to find a great gift that mum is sure to love on Mother’s Day? If so, you should consider getting her some flowers. When it comes to gifts from the heart, there is nothing like flowers. Flowers are a unique, universal gift that is appropriate for almost any situation.