spt

SPT is an acronym used for several distinct concepts across science, technology, and law, and its meaning depends on the context.

South Pole Telescope (SPT): A 10-meter submillimeter telescope located at the Amundsen-Scott South Pole Station. Operated by an international collaboration, it studies the cosmic microwave background and large-scale structure, including galaxy clusters identified via the Sunyaev-Zel'dovich effect. Notable instruments include SPTpol and SPT-3G.

Serine palmitoyltransferase (SPT): A key enzyme in sphingolipid biosynthesis. It catalyzes the first step, combining serine with palmitoyl-CoA to form 3-ketosphinganine. In humans, it comprises subunits such as SPTLC1 and SPTLC2 and is regulated by auxiliary subunits. Its activity is relevant to lipid metabolism and has been studied in metabolic and neurological disorders.

Shortest Path Tree (SPT): A concept in graph theory describing the tree formed by the union of shortest paths from a chosen source vertex to all other reachable vertices in a weighted graph. It is typically obtained via single-source shortest path algorithms, such as Dijkstra’s or Bellman-Ford, and is used in routing, network design, and related analyses.

Substantial Presence Test (SPT): A criterion in U.S. tax law used to determine whether a nonresident should be treated as a resident for tax purposes. The test evaluates days physically present in the United States over a three-year period, with specific rules and exceptions that can affect residency status.