PPR

PPR is an acronym that can refer to several terms across different fields. The intended meaning depends on the context, and the same letters are used for concepts in materials science, computer science, biology, and veterinary medicine.

Polypropylene random copolymer, or PPR, is a thermoplastic polymer used to manufacture piping systems for potable water, heating, and industrial fluids. PPR pipes offer chemical resistance, light weight, and a smooth interior that reduces friction. They are commonly joined by fusion welding or mechanical fittings, creating leak-tight joints. PPR piping is favored for hygiene and durability in many regions, though proper installation requires tools and adherence to temperature and pressure ratings.

Personalized PageRank, or PPR, is a variant of the PageRank algorithm used in graph theory and information retrieval. It computes the relevance of nodes to a specified source node by performing random walks with restarts at that node. Applications include recommender systems, link prediction, query expansion, and semi-supervised learning on graphs.

Pentatricopeptide repeat proteins, or PPR, are a large family of RNA-binding proteins defined by tandem repeats of about 35 amino acids. They are abundant in plants and regulate gene expression in mitochondria and chloroplasts, including RNA editing, processing, stability, and translation. The PPR family is diverse and central to organellar RNA metabolism.

Peste des petits ruminants, or PPR, refers to a highly contagious viral disease affecting goats and sheep. Symptoms include fever, oral lesions, and respiratory or gastrointestinal signs, with substantial mortality in susceptible flocks. Control strategies emphasize vaccination, surveillance, and movement management, with distribution concentrated in parts of Africa, the Middle East, and Asia.