OceanThe ocean (also known as the sea or the world ocean) is a body of salt water that covers approximately 70.8% of the Earth and contains 97% of Earth's water. The term ocean also refers to any of the large bodies of water into which the world ocean is conventionally divided. Distinct names are used to identify five different areas of the ocean: Pacific (the largest), Atlantic, Indian, Southern, and Arctic (the smallest). Seawater covers approximately of the planet.
Vehicle emission standardEmission standards are the legal requirements governing air pollutants released into the atmosphere. Emission standards set quantitative limits on the permissible amount of specific air pollutants that may be released from specific sources over specific timeframes. They are generally designed to achieve air quality standards and to protect human life. Different regions and countries have different standards for vehicle emissions. Many emissions standards focus on regulating pollutants released by automobiles (motor cars) and other powered vehicles.
Central and Eastern EuropeCentral and Eastern Europe is an American origin geopolitical term encompassing the countries in the Baltics, Central Europe, Eastern Europe, and Southeast Europe (primarily the Balkans), usually meaning former communist states from the Eastern Bloc and Warsaw Pact in Europe, as well as from former Yugoslavia. Scholarly literature often uses the abbreviations CEE or CEEC for this term. The Organisation for Economic Co-operation and Development (OECD) also uses the term "Central and Eastern European Countries (CEECs)" for a group comprising some of these countries.
Archaic period (North America)In the classification of the , the Archaic period in North America, taken to last from around 8000 to 1000 BC in the sequence of North American pre-Columbian cultural stages, is a period defined by the archaic stage of cultural development. The Archaic stage is characterized by subsistence economies supported through the exploitation of nuts, seeds, and shellfish. As its ending is defined by the adoption of sedentary farming, this date can vary significantly across the Americas. The rest of the Americas also have an Archaic Period.
EntisolEntisols are soils, as defined under USDA soil taxonomy, that do not show any profile development other than an A-horizon (or “A” horizon). Entisols have no diagnostic horizons, and are unaltered from their parent material, which could be unconsolidated sediment, or rock. Entisols are the most common soils, occupying about 16% of the global ice-free land area. Because of the diversity of their properties, suborders of entisols form individual Reference Soil Groups in the World Reference Base for Soil Resources (WRB): psamments correlate with arenosols, and fluvents with fluvisols.
Nitrogen trifluorideNitrogen trifluoride (NF3) is an inorganic, colorless, non-flammable, toxic gas with a slightly musty odor. It finds increasing use within the manufacturing of flat-panel displays, photovoltaics, LEDs and other microelectronics. Nitrogen trifluoride is also an extremely strong and long-lived greenhouse gas. Its atmospheric burden exceeded 2 parts per trillion during 2019 and has doubled every five years since the late 20th century. Nitrogen trifluoride did not exist in significant quantities on Earth prior to its synthesis by humans.
Law of total varianceIn probability theory, the law of total variance or variance decomposition formula or conditional variance formulas or law of iterated variances also known as Eve's law, states that if and are random variables on the same probability space, and the variance of is finite, then In language perhaps better known to statisticians than to probability theorists, the two terms are the "unexplained" and the "explained" components of the variance respectively (cf. fraction of variance unexplained, explained variation).
