Loggerhead sea turtle policies of the Barack Obama Administration (2009-2017) gear in the loggerhead conservation area during the presence of El Niño conditions in order to protect the endangered North Pacific Ocean loggerhead DPS. This ruling effective July 23, 2014 was intended to prevent bycatch of loggerhead sea turtles. A team including sea turtle biologists and oceanographers determined the presence of El Niño conditions based on the “El Niño watch” issued by the Climate Prediction Center (CPC), anomalies found in sea surface temperature (SST) charts published by NOAA’s Coast Watch Program, the presence of loggerhead sea turtles in the Pacific loggerhead conservation area, and reports of loggerhead strandings. The SST
History of manifolds and varieties History of manifolds and varieties The study of manifolds combines many important areas of mathematics: it generalizes concepts such as curves and surfaces as well as ideas from linear algebra and topology. Certain special classes of manifolds also have additional algebraic structure; they may behave like groups, for instance. In that case, they are called Lie Groups. Alternatively, they may be described by polynomial equations, in which case they are called algebraic varieties, and if they additionally carry a group structure, they are called algebraic groups. The term "manifold" comes from German "Mannigfaltigkeit," by Riemann. In English, "manifold" refers to