Loggerhead sea turtle °C (55 and 59 °F). The loggerhead takes on a floating, cold-stunned posture when temperatures drop to around 10 °C. However, younger loggerheads are more resistant to cold and do not become stunned until temperatures drop below 9 °C. The loggerheads' migration helps to prevent instances of cold-stunning. Higher water temperatures cause an increase in metabolism and heart rate. A loggerhead's body temperature increases in warmer waters more quickly than it decreases in colder water; their critical thermal maximum is currently unknown. In February 2015, a live loggerhead turtle was found floating in British Columbian waters of 10.5 °C with
History of manifolds and varieties spaces with a differentiable or topological structure, while "variety" refers to spaces with an algebraic structure, as in algebraic varieties. In Romance languages, manifold is translated as "variety" – such spaces with a differentiable structure are literally translated as "analytic varieties", while spaces with an algebraic structure are called "algebraic varieties". Thus for example, the french word "" means topological manifold. In the same vein, the Japanese word "" (tayōtai) also encompasses both manifold and variety. ("" (tayō) means various.) Ancestral to the modern concept of a manifold were several important results of 18th and 19th century mathematics. The oldest