Spörer MinimumThe Spörer Minimum is a hypothesized 90-year span of low solar activity, from about 1460 until 1550, which was identified and named by John A. Eddy in a landmark 1976 paper published in Science titled "The Maunder Minimum". It occurred before sunspots had been directly observed and was discovered instead by analysis of the proportion of carbon-14 in tree rings, which is strongly correlated with solar activity. It is named for the German astronomer Gustav Spörer.
Prices of productionPrices of production (or "production prices"; in German Produktionspreise) is a concept in Karl Marx's critique of political economy, defined as "cost-price + average profit". A production price can be thought of as a type of supply price for products; it refers to the price levels at which newly produced goods and services would have to be sold by the producers, in order to reach a normal, average profit rate on the capital invested to produce the products (not the same as the profit on the turnover).
Seriation (archaeology)In archaeology, seriation is a relative dating method in which assemblages or artifacts from numerous sites in the same culture are placed in chronological order. Where absolute dating methods, such as radio carbon, cannot be applied, archaeologists have to use relative dating methods to date archaeological finds and features. Seriation is a standard method of dating in archaeology. It can be used to date stone tools, pottery fragments, and other artifacts.
Height above mean sea levelHeight above mean sea level is a measure of the vertical distance (height, elevation or altitude) of a location in reference to a historic mean sea level taken as a vertical datum. In geodesy, it is formalized as orthometric heights. The quantity is called "metres above mean sea level" in the metric system, while in United States customary and imperial units it would be called "feet above mean sea level". Mean sea levels are affected by climate change and other factors and change over time.
Edward TufteEdward Rolf Tufte (ˈtʌfti; born March 14, 1942), sometimes known as "ET", is an American statistician and professor emeritus of political science, statistics, and computer science at Yale University. He is noted for his writings on information design and as a pioneer in the field of data visualization. Edward Rolf Tufte was born in 1942 in Kansas City, Missouri, to Virginia Tufte (1918–2020) and Edward E. Tufte (1912–1999). He grew up in Beverly Hills, California, where his father was a longtime city official, and he graduated from Beverly Hills High School.
