All articles starting with P
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Polymorphic light eruption
Polymorphic light eruption (PMLE, polymorphous light eruption, sun allergy) is the most common photodermatosis: an itchy, delayed type IV hypersensitivity rash on sun-exposed skin, affecting 10-20% of people, mostly women aged 20-40.
Polymorphic post-transplant lymphoproliferative disorder
Polymorphic post-transplant lymphoproliferative disorder, or polymorphic PTLD, is a clonal B-cell disorder driven by post-transplant immunosuppression, usually EBV-positive and often regressing when immunosuppression is reduced.
Polymorphic ventricular tachycardia
Polymorphic ventricular tachycardia (PVT, PMVT): a fast ventricular arrhythmia with beat-to-beat QRS change; includes torsades de pointes (long QT) and catecholaminergic PVT; treated with immediate defibrillation.
Polymorphism (biology)
Polymorphism (biology): occurrence of two or more alleles or morphs of a trait in one species population, conventionally least-common allele at 1% or higher; maintained by balancing selection, heterozygote advantage, frequency dependence, or mutation-selection balance, as in sickle cell and MHC polymorphism.
Polymorphism (computer science)
Polymorphism, also known as type polymorphism, is a computer science concept letting code work with values of many types, including subtype, parametric, and ad hoc polymorphism.
Polymyalgia rheumatica
Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disease of people over 50 causing shoulder, neck, and hip girdle pain and morning stiffness, treated with prednisolone 12.5–15 mg daily, and overlapping with giant cell arteritis.
Polymyositis
Polymyositis (PM) is a rare idiopathic inflammatory myopathy causing symmetric proximal muscle weakness, defined by CD8+ T-cell invasion of MHC-I-expressing muscle fibers, treated with corticosteroids and immunosuppressants.
Polymyxin B
Polymyxin B is a lipopeptide antibiotic produced by the soil bacterium Paenibacillus polymyxa, discovered in 1947 and used as a last-line treatment for multidrug-resistant Gram-negative infections.
Polymyxin resistant Acinetobacter baumannii
Polymyxin resistant Acinetobacter baumannii (PRAB, ICD-11 MG50.03): hospital pathogen resistant to last-resort colistin and polymyxin B, via pmrAB lipid A modification or LPS loss; about 13% global rate.
Polymyxin resistant Escherichia coli
Polymyxin-resistant Escherichia coli: E. coli strains resisting colistin and polymyxin B via chromosomal pmrAB/phoPQ/mgrB mutations or transferable mcr-1 through mcr-10 plasmid genes, first reported in China in 2015 and now found on five continents.
Polymyxin-resistant Pseudomonas aeruginosa
Polymyxin-resistant Pseudomonas aeruginosa: strains of P. aeruginosa resistant to colistin and polymyxin B, mainly via L-Ara4N LPS modification through PmrAB/PhoPQ and related two-component systems; global prevalence under 5%.
Polynesia
Polynesia: Pacific subregion within the Polynesian Triangle (Hawaii, Rapa Nui, Aotearoa), over 1,000 islands across 16 million square miles, defined by Polynesian Austronesian languages, Lapita-derived settlement, and traditional wayfinding.
Polynesian languages
Polynesian languages: a group of about 38 related languages within the Oceanic branch of Austronesian, descended from Proto-Polynesian in Tonga-Samoa, spread across the Polynesian triangle and outliers, including Tahitian, Samoan, Tongan, Māori, and Hawaiian.
Polynesian Mythology
Polynesian Mythology is an 1855 collection of Māori myths and legends compiled by Sir George Grey, colonial governor of New Zealand, translating 23 of 31 legends from his 1854 Māori edition.
Polynesian navigation
Polynesian navigation, or wayfinding, is non-instrument Pacific navigation by stars, swells, winds, clouds, and birds. Key facts: Sharp's accidental-voyage theory, Hōkūleʻa's 1976 Hawaii–Tahiti voyage under Mau Piailug, and the modern voyaging revival.
Polynesian Panthers
The Polynesian Panthers, formally the Polynesian Panther Party, were young Pacific Islander activists founded in Auckland, New Zealand, in 1971 to fight racism and police harassment.
Polynesian rat
Polynesian rat (Rattus exulans), also kiore or Pacific rat: smallest Rattus species, native to Southeast Asia, spread across the Pacific on Polynesian canoes; its mtDNA traces prehistoric human migration.
Polynesian settlement of Hawaii
The Polynesian settlement of Hawaii was the discovery and colonization of the Hawaiian Islands by Polynesian voyagers from Eastern Polynesia, probably the Marquesas, around the 11th to 13th centuries AD.
Polynesian Society
The Polynesian Society is a New Zealand learned society, founded in Wellington in 1892 to study Māori and other Pacific Island peoples and cultures through its journal.
Polynesian Voyaging Society
The Polynesian Voyaging Society, founded in Honolulu in 1973, revived ancient Polynesian voyaging by building the canoe Hōkūleʻa and sailing it to Tahiti in 1976 without instruments.
Polynesians
Polynesians are the indigenous peoples of Polynesia, including Hawaiians, Samoans, Tongans, Tahitians, Marquesans, and Māori, speaking Austronesian languages. They settled the Pacific from Lapita-era West Polynesia, reaching New Zealand in a 14th-century mass migration, and are famed for non-instrument wayfinding.
Polyneuropathy
Polyneuropathy is simultaneous dysfunction of many peripheral nerves, mainly length-dependent and axonal, most often from diabetes (~206 million affected). Distinguish from mononeuropathy; CIDP, small-fiber, and toxic subtypes differ in tests and treatment.
Polyneuropathy associated with IgM monoclonal gammopathy
Polyneuropathy associated with IgM monoclonal gammopathy is a rare disorder in which a monoclonal IgM protein, often anti-MAG, causes slowly progressive numbness and unsteadiness in the legs.
Polyneuropathy-hearing loss-ataxia-retinitis pigmentosa-cataract syndrome
PHARC syndrome (MIM 612674, ORPHA171848), also called peripheral neuropathy Fiskerstrand type, is a rare autosomal recessive neurodegenerative disease caused by ABHD12 mutations, combining demyelinating polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and early-onset cataract.
Polynomial
A polynomial is a mathematical expression built from powers of one or more variables multiplied by coefficients, forming the basic object of algebra and a key tool in cryptography and numerical analysis.
Polynomial cam profile
A polynomial cam profile defines a cam follower's displacement by a polynomial of the cam angle, with standard 3-4-5 and 4-5-6-7 forms ensuring smooth, continuous motion.
Polynomial chaos
Polynomial chaos is an uncertainty quantification method that represents a random model output as a series of orthogonal polynomials of the input random variables, originating in Norbert Wiener's 1938 work.
Polynomial chaos expansion
Polynomial chaos expansion (PCE) is an uncertainty quantification method that represents a model's output as a series of orthogonal polynomials in random inputs, introduced by Norbert Wiener in 1938.
Polynomial hierarchy
The polynomial hierarchy (PH) is a tower of complexity classes between P and PSPACE whose levels use a constant number of alternating quantifiers; whether it is infinite remains open.
Polynomial interpolation
Polynomial interpolation, also called interpolating polynomial, is the problem of finding the unique polynomial of degree at most n that passes exactly through n+1 given data points.