Sea levelMean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datum a standardised geodetic datum that is used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft flight levels.
DemographyDemography () is the statistical study of populations, especially human beings. Demographic analysis examines and measures the dimensions and dynamics of populations; it can cover whole societies or groups defined by criteria such as education, nationality, religion, and ethnicity. Educational institutions usually treat demography as a field of sociology, though there are a number of independent demography departments.
Home theater PCA home theater PC (HTPC) or media center computer is a convergent device that combines some or all the capabilities of a personal computer with a software application that focuses on video, photo, audio playback, and sometimes video recording functionality. Since the mid-2000s, other types of consumer electronics, including game consoles and dedicated media devices, have crossed over to manage video and music content. The term "media center" also refers to specialized application software designed to run on standard personal computers.
